chapter 3 dipolar cycloaddition ofpara-quinones and...

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CHAPTER 3 DIPOLAR CYCLOADDITION OFpara-QUINONES AND para-QUINONEIMIDES WITH CARBONYL YLIDES 3.1. INTRODUCTION l,3-Dipolar cycloaddition reaction has emerged as a very powerful tool for the construction of heterocyclic compounds. This general concept was developed by the monumental effort of Huisgen and co-workers.' 1,3-Dipolar reactions are bimolecular in nature and involve the addition of a 1,3-dipole to a multiple ir-bond system leading to five-membered heterocycles (Figure 1). Many 1,3-dipoles are readily available and react with a variety of dipolarophiles in highly regio and stereoselective manner.2 This has been used to advantage in the synthesis of many natural products.3 In recent years there has been a growing interest in the use of carbonyl ylides as 1,3-dipoles in total synthesis.4 The dipolar cycloaddition of these species to alkenic, alkynic and hetero multiple bonds affords structurally complex heterocyclic compounds in single step, often in excellent yields. Figure 1 Several methods are available for the generation of carbonyl ylides. These include the thermal and photochemical opening of oxiranes5 (often containing electron-attracting groups), the thermal fragmentation of certain heterocyclic structures such as A~-1.3.4-oxadiazolines6 or 1,3-dioxolan-4-ones (Scheme 1)' and the reaction of carbenes and carbenoids with carbonyl

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Page 1: CHAPTER 3 DIPOLAR CYCLOADDITION OFpara-QUINONES AND …shodhganga.inflibnet.ac.in/bitstream/10603/590/10/10_chapter3.pdf · In this case also, all the spectra were in agreement with

CHAPTER 3

DIPOLAR CYCLOADDITION OFpara-QUINONES AND

para-QUINONEIMIDES WITH CARBONYL YLIDES

3.1. INTRODUCTION

l,3-Dipolar cycloaddition reaction has emerged as a very powerful tool

for the construction of heterocyclic compounds. This general concept was

developed by the monumental effort of Huisgen and co-workers.' 1,3-Dipolar

reactions are bimolecular in nature and involve the addition of a 1,3-dipole to a

multiple ir-bond system leading to five-membered heterocycles (Figure 1).

Many 1,3-dipoles are readily available and react with a variety of dipolarophiles

in highly regio and stereoselective manner.2 This has been used to advantage in

the synthesis of many natural products.3 In recent years there has been a

growing interest in the use of carbonyl ylides as 1,3-dipoles in total synthesis.4

The dipolar cycloaddition of these species to alkenic, alkynic and hetero

multiple bonds affords structurally complex heterocyclic compounds in single

step, often in excellent yields.

Figure 1

Several methods are available for the generation of carbonyl ylides.

These include the thermal and photochemical opening of oxiranes5 (often

containing electron-attracting groups), the thermal fragmentation of certain

heterocyclic structures such as A~-1.3.4-oxadiazolines6 or 1,3-dioxolan-4-ones

(Scheme 1)' and the reaction of carbenes and carbenoids with carbonyl

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Chapter 3 110

derivatives (Scheme 2).' Recent developments show that carbonyl ylides can be

generated reductively from a, a'-dihaloethers using M ~ I P ~ C I ~ ~ or Sm(0)/12. 10

Scheme 1

Scheme 2

The intramolecular reaction of carbenes with neighboring carbonyl group

results in the formation of cyclic carbonyl ylides.LL This approach, pioneered by

Ibata and co-workers, allows for the convenient generation of various five- and

six-membered carbonyl ylides, which can be trapped by z-bonds. Generation of

the carbene center involves treating a diazocompound with an appropriate

transition metal catalyst. In this regard, Rh(I1) carbenoids deserve special

mention as they give consistently high yields of the cycloadduct (Figure 2)12.

Figure 2

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This tandem cyclization-cycloaddition of rhodium carbenoids, a

methodology developed by Padwa, has been employed in the construction of a

variety of' heterocycles. Some of' the important examples are given in the

following sections

Carbonyl ylide generated from o-(alkoxy carbony1)-a-diazoacetophenone

is readily trapped by various dipolarophiles such as benzaldehyde, dimethyl

acetylenedicarboxylate (DMAD) or N-phenylmaleimide to afford the corresponding

cycloadducts (Scheme 3).13

0 OMe

Scheme 3

This methodology works equally well in intramolecular cases also. Thus

the intramolecular trapping of the carbonyl ylide formed by the decomposition

of the diazoketone I afforded 8-ethoxy-1-methyl-9-oxatricyclo[3.2.1.l]nonan-2-

one as the major product.14 Here the initially formed carbonyl ylide adds to the

tethered olefin to yield the cycloadduct (Scheme 4). r 7

Scheme 4

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Tandem cyclization-cycloaddition of rhodium carbenoids has been

employed as the key step in several natural product synthesis. For example, the

key intermediate 11 in the synthesis of the sesquiterpene (+)-Illudin-M is

prepared using this methodology as illustrated in Scheme 5.15

illudin M

Scheme 5

Limited efforts have been made to trap carbonyl ylides, formed by the

Padwa protocol, with aza dipolarophiles. In an early report, the carbonyl ylide

formed from the diazoketone 111 is trapped with Mander's reagent to afford the

corresponding cycloadduct (Scheme 6).16

Scheme 6

In a related report, irnines are used as dipolarophiles to trap carbonyl

ylides generated in situ from 1V (Scheme 7)."

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Ph

OMe OMe R

IV R = S02Ph, Me

Scheme 7

As far as the addition of carbonyl ylides to diones and quinones are

concerned, only scant reports are available in the literature. Earlier

investigations carried out in our own laboratory have established that cyclic

carbonyl ylides, five- and six-membered, generated by the Padwa protocol add to

o-quinones (Scheme 8).lX The spiroheterocycle so formed undergoes a number

of interesting synthetic transformation^.'^

Scheme 8

o-Quinones proved to be efficient traps even for the seven membered

carbonyl ylide dipoles (Scheme 9).'* This is remarkable, in view of the fact that

in this case insertion of the solvent to the initially formed carbenoid competes

successfully with the cyclization of the latter to seven membered ylide.

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Scheme 9

Isatin and its derivatives can act as dipolarophiles towards the addition of

carbonyl ylides as illustrated in the following However, in this case

five- and six-membered ylides gave the desired cycloadduct while seven

membered ylide failed to afford any product.

Scheme 10

3.1.1. Present study

It is worth mentioning that even though carbonyl ylides generated by

Padwa protocol have been added to a variety of dipolarophiles both

intermolecularly and intramolecularly, their addition to quinonoid compounds

has not been investigated. Results from our own group indicated that 1,2-diones

and o-benzoquinones act as efficient dipolarophiles towards carbonyl ylides.

Therefore we tried to explore the scope of this process by employing 1,4-

quir~ones as the trap. I he study was then expatiated to p-quinoneimides also.

Additional impetus came from the fact that efforts to add carbonyl ylide dipoles

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to aza dipolarophiles have been scant. It is also noteworthy that p-

quinoneimides are rather underexplored systems compared to p-quinones

especially with regard to dipolar cycloaddition reactions. The quinonoid

compounds chosen and the carbonyl ylide precursors employed in the current

study are depicted in Figure 3 and Figure 4 respectively.

l a : R = H 2a: R = Me, R' = S02Ph 1b: R = M e 2b: R = H, R' = Ts

Figure 3

Figure 4

3.2. RESULTS AND DISCUSSION

3.2.1. Reaction of carbonyl ylides withp-quinones

In the initial experiment, p-benzoquinone was treated with the carbonyl

ylide precursor 4a in presence of 2 mol% of ~ ( O A C ) ~ in benzene at room

temperature. The carbonyl ylide, formed in situ, added to C=O moiety of p-

quinone affording the cycloadduct 6a in good yields (Scheme 11).

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Chapter 3

i) Rh2(0Ac)4, benzene, rt, Ar, 45 min, 64%

Scheme 11

The structure of the adduct was elucidated on the basis of spectroscopic

analysis. In the IR spectrum, band due to keto carbonyl of 6a was seen at 1726

cm-' while the quinone carbonyl absorption occurred at 1684 cm-I. In 'H NMR,

the bridgehead proton characteristically resonated at 64.44. The two methylene

groups present in the molecule gave separate multiplets centered at 62.72 and 6

2.49. The signals due to the protons of the dienone moiety were seen at 66.79,

6.62, 6.37 and 5.15 as doublets while the aromatic protons were discernible as

two separate rnultiplets centered at 67.59 and 7.41. In I3c the bridgehead

methine carbon gave signal at 6 77.32 while the acetal carbon at the bridgehead

was discernible at 1 10.67 The characteristic signal due to the spiro carbon was

visible at 6 86.83. 'The signal due to the keto carbonyl materialised at 6202.48

while that of dienone carbonyl was present at 6 183.85. All the other signals

were in agreement with the structure assigned. The compound also afforded

satisfactory elemental analysis.

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Figure 5: 'H NMR spectrum of 6a

Figure 6: I3c NMR spectrum of 6a

Sinrlar reactivity was observed with the carbonyl ylide precursor 4b and

~-4uinone. Here also the carbonyl ylide. formed in ritu, added to the C=O of

quinone (Scheme 12 ).

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i ) Rhz(OAc)b, benzene, rt, Ar, 45 min., 58%

Scheme 12

In the IR spectrum of 6b, characteristic absorptions for the keto and

dienone carbonyls were observed at 1728 cm-' and 1686 cm-'. The resonance

signal due to the bridgehead proton was discernible at 6 4.28 in 'H NMR

spectrum. In I3c NMK spectrum, characteristic signals due to the spiro carbon

and bridgehead methine carbon were seen at 6 86.45 and 77.14 respectively.

The carbonyl resonances were observed at 6202.98 and 183.78.

Carbonyl ylide generated h m precursor 4c also added in a similar way to

phmquinone aEord'ig the corresponding spiro bicyclic compound 6c in good yield

(Scheme 13).

i) Rhz(OAc)4, benzene, rt, Ar, 45 min., 61%

Scheme 13

Ln the 1R spectrum of 6c, the characteristic keto and dienone carbonyls

were observed at 1728 and 1685 cm-' respectively. In 'H NMR, the signal at 6

4.32 was typical of the bridgehead proton present in 6c. In the I3c NMR

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spectrum, the two carbonyl absorptions were visible at 6 202.28 and 181.46

while the signal due to the spiro carbon was discernible at 686.91.

We then employed 25-dimethyl-p-benzoquinone in this reaction. Thus

with the diazo compound 4a, 2,5-dimethyl-p-benzoquinone afforded the

analogous product in good yield (Scheme 14).

i) Rh2(0Ac)4, benzene, rt, Ar, 45 min., 72%

Scheme 14

In the IR spectrum, the absorptions due to keto and dienone carbonyls

were observed at 1731 and 1682 cm-I respectively. In 'H NMR, the bridgehead

proton was discernible at 6 4.41. The two protons in the dienone moiety gave

signals at 6 6.36 and 5.99 whereas peaks due to methyl groups were seen at 6

1.91 and 1.75, as singlets. In "C NMR spectrum, the carbonyl resonances were

discernible at 6 202.41 and 18 1.37. 'The peak at 6 85.81 was typical of the spiro

carbon present in 7a. Signal corresponding to the bridgehead methine carbon

was seen at 677.81 while the other bridgehead carbon (acetal) displayed signal

at 6 110.83. All other signals'were in accordance with the structure proposed.

To establish the stereochemistry of the adduct, we resorted to nOe

difference NMR spectroscopy. In the nOe difference spectrum, the proton at 6

6.36 showed 6% enhancement when the proton at the bridgehead at 64.41 was

irradiated while the signal at 6 5.99 showed little enhancement. To reaffirm the

proposed stereochemistry, the signal at 6 5.99 was irradiated when only the

methyl protons appearing at 6 1.75 showed enhancement, with the signal at 6

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4.41 remaining unaffected. These results indicated that the proton at 66.36 is in

closer proximity to the bridgehead proton than the proton coming at 65.99.

Analogous reactivity was observed when the carbonyl ylide precursor 4b

was employed in the reaction (Scheme 15).

i) Rhz(OAc)4, benzene. r t , Ar, 45 rnin., 68%

Scheme 15

Here again, the characterization of the product was effected by

spectroscopic analysis. The absorptions at 1729 cm-' and 1682 cm-' in IR

spectrum were indicative of the keto and dienone carbonyls present in 7b. In 'H

Nh.IR, typical signal due to the bridgehead proton was visible at 6 4.39. The

dienone protons were discernible at 6 6.41 and 5.96 as singlets. The signals due

to three methyl groups were observed at 6 1.94, 1.76 and 1.71 as singlets. In I3c NMR, the signal at 6 86.4'7 was typical of the spiro center present in the

molecule. The signals at 6 110.35 and 77.43 were attributed to the resonances of

the bridgehead carbons. The carbonyl groups were discernible at 6 203.82 and

182.58. All other peaks were in ag~eement with the structure assigned.

The thiophene-derived carbonyl ylide precursor 4c also reacted in a

similar manner affording the corresponding product in good yield (Scheme 16).

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1) Rhz(OAc)d, benzene, rt, Ar, 45 min., 65%

Scheme 16

In this case also, all the spectra were in agreement with the structure

proposed. Absorptions at 1731 cm-' and 1684 cms' in the vibrational spectrum

were typical of the keto and dienone carbonyl stretchings. In 'H NMR, signal

due to bridgehead proton was discernible at 6 4.34 as a singlet. The keto

carbonyl and dienone carbonyl present in 7c gave signals at 6 203.41 and

182.35 in ' 3 ~ NMR spectrum. Signal due to spiro carbon was discernible at 6

78.63 while the bridgehead methine carbon resonated at 6 87.91. All other peaks

also agreed well with the structure assigned.

3.2.2. Reaction of carbonyl ylides withp-quinoneimides

We then extended our studies to include p-quinoneimides, a much less

studied class of quinonoid compounds. Thus 2,5-dimethyl-p-quinoneimide 2a

when treated with five-membered cyclic carbonyl ylide precursor 3 in presence

of 2 mol% of Rhz(OAc), in benzene afforded the cycloadduct 8 in good yield.

In this case, the carbonyl ylide generated in situ added to C=C bond of the

quinoneimide (Scheme 1 7).

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2a 3 8

I ) Rh2(0Ac),,, benzene, rt, 30 rnin., 75%

Scheme 17

The structure of the adduct was established on the basis of spectroscopic

analysis. In the IK spectrum, absorption due to the carbonyl group present in 8

was seen at 1733 cm-I. The band at 1579 cm-' corresponded to the C=N

vibrations. In 'H NMR spectrum, signal due to angular proton in the adduct was

discernible at 6 4.41 as a singlet while signal corresponding to bridgehead

proton was present at ti 4.37. The angular methyl group gave signal at 6 2.18

while the bridgehead methyl group displayed signal at 6 1.38, both as singlets.

The signal due to alkene proton of 8 appeared together with four of the aromatic

protons as a multiplet centered at 6 7.95, while the rest of the aromatic protons

gave another multiplet centered at 6 7.60. The protons of the cyc,lopropyl ring

gave three multiplets, one centered at 6 1.46, another at 6 1.33 and yet another

at 6 1.15. In "C NMR spectrum. the signal at 6 208.68 corresponded to

carbonyl resonance. Two imine carbons were discernible at 6 176.85 and

176.46. The methine carbon atom at the bridgehead manifested signal at 690.1 1

while signal due to other bridgehead carbon was observed at 6 89.93. The

signals at 6 58.92 and 54.12 were due to the resonance of the carbon atoms at

the [6,6] fusion. Spiro carbon in the cyclopropyl group was discernible at 6

42.48 while the three methyl groups present in the molecule gave signals at 6

21.42, 19.34 and 15.56. Signals due to cyclopropyl carbon resonances were

observed at 15.41 and 12.72.

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----. . - 7 - - T -. - --- 7 --- 2 1 D F

Figure 7: 'H NMR spectrum of 8

Figure 8: I 3 c NMR spectrum of 8

To establish the structure with c o ~ ~ e c t stereochemistry, we resorted to

NOESY analysis (Figure 9). In the NOESY spectrum, strong cross peaks

occurred between H-6 and Me-14 protons and between H-l l and Me-13

protons. Cross peaks were also discernible between H-4 and Me-14 protons and

H-6 and Me-13 protons. ofbelt, with low intensity. These results suggested that

both Me-14 and H-6 protons occupied endo position of the bicyclic core.

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Figure 9: NOESY spectrum of 8

Further support for these results came from nOe difference analysis

(Figure 10). The signal due to H-4 (6 4.39) showed 2% enhancement on

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irradiating Me-14 protons Similarly. 1% enhancement for H-6 signal occurred

when Me-13 protons were irradiated l'hese rather low values for signal

enhancement are typlcal of exo isomer In the case of endo isomer, one would

expect the correspond~ng signal enhancement in the range 5-7%.

Figure 10: Selected NOE data for 8

Similar reactivity was observed with ring unsubstituted p-quinoneimide

also. In this case, the initially formed cycloadduct tautomerised to the

corresponding aromatic compound (Scheme 16).

NTs

i) R h ~ ( o A c ) ~ , benzene, rt, Ar, 30 min, 58%

Scheme 18

As usual, the structure assignment for the compound 9 is based on

spectroscopic data. The band due to NH absorption was seen at 3336 cm-' in IR

spectrum while the band at 1732 was attributed to the carbonyl group present in

9. In IH NMR, characteristic signal due to the bridgehead proton was seen at 6

4.73 as a singlet while protons in the cyclopropyl ring gave three multiplets

centered at S 1.55, 1.25 and 1.04. In 13c NMR spectrum, the carbonyl signal

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Chapter 3 126

was discernible at b 204.32. The resonance due to bridgehead methine carbon

was observed ar b 90 87 while the other bridgehead carbon gave signal at 6

86.91. The cyclopropyl fused spirocarbon resonated at 6 42.48 while the other

cyclopropyl carbons were d~scernible at 6 15.47 and 12.38.

The same reactlon proceeded equally well with six-membered cyclic

carbonyl ylides also. Diazo compound 4a reacted with 2,5-dimethyl-p-

benzoquinone dibenzenesulfonimide under Rh(I1) catalysis affording the

analogous product IOa in good yield (Scheme 19).

N S O ~ P ~ o P ~ C

i) Rh(ll), benzene, rt, Ar, 30 min., 68%

Scheme 19

In the IR spectrum, the absorption bands at 1734 cm-' and 1581 cm-'

indicated the presence of keto and imido functionalities in 10a. In 'H N m the

bridgehead proton was discernible as a singlet at 6 4.72 while signal due to

angular proton was seen at 6 4.87. The "C NMR spectrum of 10a agreed well

with the structure proposed. Resonance due to carbonyl carbon was observed at

6 204.52 while the two inlido carbon signals were observable at 6 177.25 and

176.56. The bridgehead methine carbon gave signal at 6 90.96 while the

quaternary carbon at the bridgehead was discernible at 87.01. The signal due to

the two ring junct~on carbon atoms were seen at 659.44 and 58.68.

Diazo compound 4b derived from levulinic acid also behaved in a similar

manner. Here again, the six-membered carbonyl ylide, formed in situ from 4b,

added to C=C of the quinoneimide moiety (Scheme 20).

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angular and bridgehead protons were discemible at 6 4.91 and 4.66 as singlets

while methyl groups presenl in 1Oc gave two singlets at 6 1.44 and 1.34. In I3c NMR spectrum, resonance due to the carbonyl group was observed at 6203.43

while the imido group signals were discemible at 6 177.81 and 177.10. The

bridgehead methine carbon resonated at 6 90.97 while the other bridgehead

carbon gave signal at 6 86.50. The signals due to the two ring junction carbon

atoms appeared at 6 59.24 and 58.2 1 .

Ring unsubstituted p-quinoneimide Zb, when treated with six-membered

cyclic carbonyl ylide precursor 4a in presence of catalytic amounts of Rh(II),

afforded the cycloadduct Lla in good yield. Here the initially formed adduct

underwent tautomerization to the fully aromatic derivative (Scheme 22).

2b 4a l l a

i) Rhz(OAc)a, benzene, rt, Ar, 30 min., 52%

Scheme 22

In the IR spectrum of lla, characteristic carbonyl absorption was

observed at 1729 cm-' while band due to NH group was seen at 3331 cm-'. In 'H

NMR, the distinctive bridgehead proton signal was discernible at 65.21 as a singlet.

The ' 3 ~ NMR spectrum also agreed well with the structure proposed. The

carbonyl carbon resonance was observed at 6 200.31. While signals due to

methyl carbons of the tosyl group were discernible at 620.86 and 20.35.

Carbonyl ylide precursor 4 b derived &om levulinic acid also reacted

analogously with Zb, affording the adduct llb in moderate yield (Scheme 23).

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Chapter 3

tTS l i 11 'I'

NTs 2b

T ~ H N l l b

1) Rhz(OAc)4, benzene, rt, Ar, 30 rnin., 48%

Scheme 23

The structure of the adduct was ascertained by spectroscopic analysis in

the usual manner. In the IR spectrum, the bands at 3345 cm-I and 1727 cm-I

were due to NH and C=O groups present in the molecule. The characteristic

bridgehead proton was observable in 'H NMK at 65.24 as a singlet. The signal

corresponding to methyl groups were discernible at 6 2.37, 2.34 and 1.78 as

separate singlets. In "c' NMR, carbonyl resonance was observed at 6 201.34.

The signals due to two bridgehead carbon atoms were discernible at 686.21 and

684.78. The compound also afforded satisfactory elemental analysis.

Carbonyl ylide derived from the thiophene substituted diazo compound

4c reacted with p-quinone dltoluenesulfonimide 2b as shown in the following

Scheme.

2b 4c I l c

i) RhAOAc),, benzene, rt, Ar, 30 min., 51%

Scheme 24

As usual, characterization of the product was carried out with the aid of

spectroscopic data. The peaks at 3331 cm" and 173 1 cm-I in the IR spectrum

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Chapter 3 130

corresponded to the absorptions of WH and C=O groups present in l l c . In 'H

NMR, peak at h' 3.91 was typical of the bridgehead proton present in the

structure. The "C NMK spectrum t'urnished further support to the structure

proposed. Resonance due to the carbonyl carbon was seen at 6 202.19 while

bridgehead methine signal was observed at 6 88.51. The other bridgehead

carbon was discernible at. 6 86.78.

In conclusion. our studies on the dipolar cycloaddition of carbonyl ylides

to FI-quinones and p-quinoneimides have revealed that the methodology offers a

versatile protocol for the construction of complex heterocyclic systems. Due to

the presence of inherent functionalities, these compounds are amenable to a

number of synthetic transformations. Most importantly, we have shown that

quinoneimides can act as efficient traps for carbonyl ylides, which can be

extended to other dipolar species as well.

3.3. THEORETICAL CONSIDERATIONS

From the results presented in the previous section, it is obvious that

cyclic carbonyl ylide dipoles add across C=O in the case ofp-quinones and C=C

in the case of p-quinoneimides. In order to afford a theoretical rationale for the

observed resuits, we have carried out some calculations using semi-empirical

MNDO method with the aid of TIT.4N software (version 1). '' The frontier molecular orbitals for p-quinone-carbonyl ylide reaction are

given in Figure 1 I . In this case the predominant stabilizing interaction is

between the HOMO of the dipole and LUMO of p-quinone, a typical example

of Type I cycloaddition according to the Sustmann classification. It is also

evident from the figure that LUMO of p-quinone has larger coefficients on

atoms constituting C'=O than on atoms in C=C. This explains, at least

rationalises, why the addition of carbonyl ylides occurs across the C=O rather

than C=C in the case ofp-quinone.

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Figure 11

In the case of p-quinoneimide also, the predominant stabilizing

interaction is between HOMO of the dipole and the LUMO of quinoneimide

(Figure 12). However in this case, the LUMO of the quinoneimide is oriented

more along C=C than along C=N and hence addition occurs exclusively across

that bond.

e n e r 9 Y

h

0.36247-3

-0.35650 P O 33014 , - ev

o , AE LuMO = 6.63623 % o -0 35465

',AE = 9.84238

-8.13396 ev HOMO -10.73373 ev

HOMO

0

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LUMO

0

0.34928 ,, / .".,AE = 9.26294 ev

-8.1 3396 ev HOMO \-

-10.15429 HOMO

Figure 12

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Chapter 3 133

3.4.EXPEKIMENTAL

General information about the experiments is given in Chapter 2. The

melting points reported are for compounds rec~ystallised tiom dichloromethane-

hexam solvent system

5'-Phenylspiro[2,5-cyclohexadiene-1,7'-[6,8]dioxabicyclo[3.2.l]octane]4,2'4ione

(6a)

To a benzene solution (4 mL) of the diazoketone 4a (101 mg, 0.50 mmol) at

room temperature under argon atmosphere was added p-benzoquinone l a (43

mg, 0.40 mmol) and stirred for 5 rnin., before adding 1-2 mg of Rh(I1) acetate.

The resulting solution was stirred for 45 min. and filtered over a small pad of

Celite and washed with more solvent. The filtrate was concentrated and the

residue on silica gel column chromatography afforded analytically pure 6a (72

mg, 64%) as colorless crystalline solid. mp. 130-132 "C

IR (cm-') : 1726, 1684, 1601, 1434, 1162, 1082, 778,

689

' H NMR : 7.60-7.57 (m, 2H), 7.42-7.40 (m, 3H),

6.79 (d, lH, J = 10.1 Hz), 6.62 (d, lH, J =

10.3Hz),6.37(d, lH , J = 10.3Hz),6.15

(d, lH, J = 10.1 Hz) ,4 .44(~, 1H),2.82-

2.62 (m, 2H), 2.52-2.47 (m, 2H)

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Chapter .3 134

5'-methylspiro[2,5-cyclohexadiene-i,7'-[6,8]dioxabicyclo[3.2.i]octane]-4,2'-dione

(6b)

The reaction of diazoketone 4b (73 mg, 0.50 mn~ol) andp-benzoquinone l a (43,

0.40 mmol) according to the general procedure afforded 6b (51 mg, 58%) as a

colorless crystalline solid. mp. 1 18- 120 "C

IK(cm-I) : 3021, 2978, 1728, 1686, 1442, 1184,

1078,791,714

'H NMR : 6.90 (d, lH , J = 10.1 Hz), 6.49 (d, lH, J =

10.2 Hz), 6.32 (d, lH, J = 10.2 Hz), 6.22

(d, lH, J = 10.1 Hz),4.28 (s, 1H),2.64-

o 2.51 (m, 2H), 2.27-2.21 (m, 2H), 1.73 (s,

3H)

"C NMR : 202.98, 183.78, 146.97, 141.41, 132.20,

128.22, 110.28, 86.45, 77.14, 33.11,

32.77, 25.30

5'-Thienylspiro[2,5-cyclohexadiene-I ,7'~6,8]dioxabicyclo[3.2.l]octane]4,2'dione (6c)

The reaction of diazoketone 4c (104 mg, 0.50 mmol) and p-benzoquinone l a

(43, 0.40 mmol) according to the general procedure afforded 6c (70 mg, 61%)

as a colorless crystalline solid. mp. 144-145 OC

~ ~ ( c m - ' ) : 3045, 2983, 1728, 1685, 1567, 1513,

(KBr) 1442,1138,798,669

'H NMR : 7.39 (d, lH, J = 6.8 Hz), 7.28 (d, lH, J =

6.8 Hz), 7.06 (d, lH, J = 6.8 Hz), 6.75 (d,

lH, J = 10.2 Hz), 6.64 (d, lH , J = 10.2

Hz), 6.33 (d, lH, J = 10.2 Hz), 6.14(d,

lH, J = 10.2 Hz), 4.32 (s, lH), 2.86-2.66

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(m, 2H), 2.60-2.52 (m, 2H)

2,5-Dimethyl-5'-phenylspiro[2,5-cyclohexadiene-l,7'-[6,8]dioxabicyclo[3.2.l]octane).

4,T-dione (7a)

The reaction of diazoketone 4a (101 mg, 0.50 mmol) and p-benzoquinone l b

(54 mg, 0.40 mmol) according to the general procedure afforded 7a (96 mg,

72%) as a colorless crystalline solid. mp. 138-140 "C

IR (cm-') 3031, 2917, 1731, 1682, 1603, 1452,

(KBr) 1138,1061,729

'H NMR : 7.61-7.29 (m, SH), 6.36 (s, lH), 5.99 (s,

% lH), 4.41 (s, lH), 2.76-2.67 (m, 2H),

2.52-2.46 (m, 2H), 1.91 (s, 3H), 1.75 (s, $

0 3H)

''c NMR : 202.41, 181.37, 148.34, 141.57, 139.62,

129.42, 128.91, 128.43, 128.19, 121.72,

110.83, 85.81, 77.81, 34.82, 33.17, 16.91,

15.27

HRMS calcd for ClgH1804: 3 10.12050 found 3 10.12045

2,5-Dimethyl-5'-methylspiro[2,5~yclohexadiene-l,7'-[6,8]dioxabicyclo[3.2.l]octane]-

4,2'-dione (7b)

The reaction of diazoketone 46 (70 mg, 0.50 mmol) andp-benzoquinone l b (54

mg, 0.40 mmol) according to the general procedure afforded 7b (67 mg, 68%)

as a colorless crystalline solid. mp. 134- 135 OC

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Chapter 3 136

'H NMR 6.41 (s, lH), 5.96 (s, lH), 4.39 (s, lH),

2.78-2.69 (m, 2H), 2.54-2.47 (m, 2H),

o 1.94 (s, 3H), 1.76 (s, 3H), 1.7 1 (s, 3H)

I3c NMR : 203.82. 182.58, 147.32, 137.41, 128.33,

121.60. 110.35, 86.47, 77.43, 35.71,

33.91, 24.71, 16.83, 15.42

2,5-Dimethyl-5'-thienylspiro[2,5cyclohexadil,7'-[6,8]dioxabicyclo[3.2.l]octane]-

4,2'dione (7c)

The reaction of diazoketone 4c (104 mg, 0.50 mmol) and p-benzoquinone l b

(54 mg, 0.40 mmol) according to the general procedure afforded 7c (82 mg,

65%) as colorless crystalline solid. mp. 15 1-153 "C

IR (cm-') : 3013, 2979, 1731, 1684, 1601, 1434,

(KBr) 1331, 1132, 1110,961,746

'H NMR : 7.41 (d, lH, J = 6.4 Hz), 7.25 (m, lH),

7.06 (d, lH, J = 6.4 Hz), 6.44 (s, lH),

5.91 (s, lH), 4.34 (s, lH), 2.79-2.65 (m,

2H), 2.56-2.47 (m, 2H), 1.78 (s, 3H), 0

1.69 (s, 3H)

IJc NMR : 203.41, 182.35, 148.42, 146.15, 141.21,

137.55, 137.28, 128.91, 126.40, 121.81,

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Cycloadduct 8

The reaction of'diazoketone 3 (76 mg, 0.50 mmol) and p-benzoquinonediimide

2a (165 mg, 0.40 mmol) according to the general procedure afforded 8 (161 mg,

75%) as colorless crystalline solid. mp. 148-149 O C

~ ~ ( c m - ' ) : 3041, 2981, 1733, 1601, 1579, 1461,

(KBr) 1333, 11 10,979,761

' H NMR : 7.97-7.93 (m, 5H), 7.65-7.56 (m, 6H),

4.41 (s, lH), 4.37 (s, IH), 2.18(s, 3H), 0 &%Ns02Ph 1.50-1.42 (m, 2H), 1.38 (s, 3H), 1.34-

Y : 1.31 (m, lH), 1.28 (s, 3H), 1.16-1.13 (m,

Ph0,SN 1H)

I3c NMR : 208.68, 176.85, 176.46, 151.92, 140.78,

140.64, 133.80, 13.36, 133.16, 129.08,

129.03. 127.15, 90.11, 89.93, 58.92,

54.12, 42.48, 21.42, 19.34, 15.56, 15.41,

12.72

Cycloadduct 9

The reaction of diazoketone 3 (76 mg, 0.50 mmol) and p-benzoquinonediimide

2b 165 mg, 0.40 mmol) according to the general procedure 9 (124 mg, 58%) as

colorless crystalline solid. mp. 194-196 OC

1R (crn") : 3336, 3041, 2979, 1732, 1603, 1334,

(KBr) 1 109,93 1,767

'H NMR : 9.78 (s, lH , exchangeable with D20),

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9.54 (s, lH, exchangeable with DzO),

7.62-7.56 (m, 4H), 7.34-7.29 (m, 4H),

6.81 (d, lH, J = 6.8 Hz), 6.76 (d, lH , J =

6.8 Hz), 4.73 (s, lH), 2.38 (s, 3H), 2.31

(s, 3H), 1.78 (s, 3H), 1.59-1.51 (m, 2H),

1.29-1.22 (m, lH), 1.08-1.01 (m, 1H)

' 3 ~ ~ ~ ~ : 204.32, 142.71, 141.92, 139.38, 139.07,

136.71, 136.21, 129.53, 12932, 128.27,

127.85, 126.75, 126.64, 122.15, 119.93,

90.87, 86.91, 42.48, 21.71, 21.34, 19.78,

15.47, 12.38

1-Phenyl-3,6-bis(phenylsulfonylimino)d,7-dimethyl-l2-oxa-tricyclo[6.3,i.O]dodec-

4-ene-9-one (10a)

The reaction of dlazoketone 4a (101 rng, 0.50 mmol) and p-

benzoquinonediimide 2a (165 mg, 0.40 mrnol) according to the general

procedure afforded 10a (160 mg, 68%) as colorless crystalline solid. mp. 108-

109 "C

IR (cm-') 3021, 2963, 1734, 1603, 1581, 1438,

(KBr) 1331,1168, 1079,963,762

'H NMR : 7.99-7.93 (m, 4H), 7.65-7.51 (m, 8H),

7.32-7.25 (m, 4H), 4.87 (s, lH), 4.72 (s,

lH), 3.12-3.04 (m, lH), 2.78-2.73 (rn,

Ph02SN 2H), 2.37-2.30 (rn, lH), 1.35 (s, 3H),

1.15 (s, 3H)

"C NMR 204.52, 177.25, 176.56, 154.25, 140.76,

140.52, 139.97, 133.40, 129.56, 129.12,

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129.06, 128.20, 127.96, 127.16, 127.09,

126.04, 90.96, 87.01, 59.44, 58.68, 35.97,

33.50,20.08, 18.19

HRMS Calcd for C J I H ~ ~ N ~ O ~ S ~ : 588.138881 Found 588.138084

1-Methyl-3,6-bis(phenylsuIfonylimino)-4,7-dimethyl-l2-oxa-tricyclo[6.3,l.OJdodec-

4-ene-9-one (lob)

The reaction of diazoketone 4b (70 mg, 0.50 mmol) andp-benzoquinonediimide

2a (165 mg, 0.40 mmol) according to the general procedure afforded lob (134

mg, 64%) as colorless crystalline solld. mp. 97-98 O C

1R (cm-') 3023, 2979, 1732, 1604, 1572, 1461,

(KBr) 1333,741

'H NMR : 7.92-7.87 (m, 5H), 7.63-7.55 (m, 6H),

4.84 (s, lH), 4.76 (s, lH), 3.08-3.01 (m,

lH), 2.79-2.75 (m, ZH), 2.38-2.30 (m,

P~O,SN IH), 1.87 (s, 3H), 1.41 (s, 3H), 1.27 (s,

3H)

''c NMR : 205.12, 177.31, 176.89, 150.12, 141.31,

140.92, 133.71, 133.18, 133.01, 128.97,

128.79, 127.64, 90.32, 87.12, 59.43,

58.41, 35.81, 34.19, 24.41, 21.38, 19.47

1-Thienyl-3,6-bis(phenylsulfonylimino)-4,7-dimethyl-l2-oxaf icyclo[6.3.l.O]dodec.

4-ene-9-one (10c)

The reaction of diazoketone 4c (104 mg, 0.50 mmol) and p-

benzoquinonediimide 2a (165 mg, 0.40 mmol) according to the general

procedure afforded 1Oc (164 mg, 69%) as colorless crystalline solid. mp. 123-124 "C

~ ~ ( c m - ' ) : 3063, 2981, 1731, 1601, 1578, 1436,

(KBr) 1331, 1162,962,771

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'H NMR : 7.98-7.94 (m, 4H), 7.56-7.64 (m, 8H),

7.15-7.18 (m, lH), 6.96-6.93 (m, lH),

4.91 (s, lH), 4.66 (s, lH), 3.14-3.08 (m,

lH), 2.75-2.70 (m, 2H), 2.36-2.47 (m,

lH), 1.44 (s, 3H), 1.34 (s, 3H)

' 3 ~ NMR 203.43, 177.81, 177.10, 153.71, 143.26,

140.72, 133.20, 129.13, 129.07, 127.16,

90.97, 86.50, 59.24, 58.21, 36.79, 33.47,

20.37, 18.60

Cycloadduct I l a

The reaction of diazoketone 4a (101 mg, 0.50 mmol) and p-

benzoquinonediimide 2b (165 mg., 0.40 mmol) according to the general

procedure afforded l l a (122 mg, 52%) as colorless crystalline solid. mp. 192-

194 "C

l ~ ( c m - I ) : 3331, 3021, 2963, 1729, 1601, 1333,

(KBr) 11 10,928,761

7JgHTs 'H NMR : 9.84 (s, lH, exchangeable with D20),

I 9.42 (s, lH, exchangeable with D20),

0 TsHN

7.63-7.35 (m, 8H), 7.244.99 (m, 5H),

6.90(d, lH, J = 7.8 Hz), 6.70 (d, lH, J =

7.8 Hz), 5.21 (s, lH), 3.29-3.25 (m, lH),

2.71-2.67 (m, 2H), 2.31-2.26 (m, lH),

2.40 (s, 3H), 2.35 (s, 3H)

"CNMR 200.31, 143.30, 142.76, 142.29, 139.35,

136.35, 136.23, 136.14, 133.64, 128.94,

128.88, 128.37, 127.95, 127.35, 126.44,

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121.32, 121.32, 85.48, 82.39, 31.73,

31.13,20.86,20.35

Cycloadduct I I b

The reaction of diazoketone 4b (70 mg, 0.50 mmol) andp-benzoquinonediimide

2b (: 165 mg, 0.40 mmol) according to the general procedure afforded l l b (1 0 1

mg, 48%) as a colorless crystalline solid. mp. 178-180 OC

'H NMR 9.81 (s, lH, exchangeable with D20),

9.57 (s, lH, exchangeable with D20),

7.57-7.42 (m, 4H), 7.31-7.26 (m, 4H),

6.89 (d, lH, J = 7.6 Hz), 6.74 (d, lH, J =

7.6 Hz), 5.24 (s, lH), 3.27-3.24 (m, lH),

2.74-2.69 (m, 2H), 2.32-2.26 (m, lH),

2.37 (s, 3H), 2.34 (s, 3H), 1.78 (s, 3H)

I3cNMR : 201.34, 143.37, 142.98, 139.76, 139.19,

136.27, 136.24, 129.78, 129.71, 128.32,

127.96, 126.82, 126.83, 122.15, 119.97,

86.21,84.78,32.76,31.94,20.64,20.34, 19.31

Cycloadduct I l c

The reaction of diazoketone 4c (104 mg, 0.50 mmol) and p-

benzoquinonediimide 2b (165, 0.40 mmol) according to the general procedure

afforded l l c (121 mg, 5 1%) as colorless crystalline solid. mp. 207-209 "C

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0 TsHN

'HNMR : 9.71 (s, lH, exchangeable with D20),

9.41 (s, lH, exchungeable with DrO),

7.51-7.37 (m, 5H), 7.29-7.21 (rn, 6H),

6.79(d, lH,J=6.4Hz),6.74(d, lH, J =

6.4Hz),4.91 (s, lH),3.19-3.11 (m, lH),

2.71-2.65 (m, 2H), 2.34-2.25 (m, lH),

2.34 (s, 3H), 2.29 (s, 3H)

'-'c NMR : 202.19, 148.47, 143.71, 143.42, 142.31,

139.76, 139.19, 136.14, 136.02, 135.82,

129.91, 129.74, 129.60, 128.51, 127.81,

126.47, 126.31, 123.47, 121.22, 88.51,

86.78, 34.51, 32.14, 22.51,21.89

3.5. REFERENCES

1. Huisgen, R. Proc. Chem. Soc. 1961,357. b) Huisgen, R. Angew. Chem..

Znt. Ed Engl. 1967. 6, 16.

2. Padwa, A. (Ed.) in .1,3-Dipolar Cycloaddition Chemistry' Wiley Inter-

science: New York, 1984, Vols 1 & 2.

3. a) Gamer, P.; Ho, W. B.; Grandhee, S. K.; Youngs, W. J.; Kennedy, V. 0.

J. Org. Chem. 1991. 56, 5893. b) Gamer, P.; Ho, W. B.; Shin, C. J Am.

Chem. Soc. 1993,115, 10742. c) MOM, J. A.; Valli, M. J. J Org. Chem.

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4. a) Hendirckson, J . R.; Farina, J . S. J. Org. Chem. 1980,45, 3359. b)

Sammes, P. Ci.; Whitby, R. J. Chem. Soc., Chem. Commun. 1984,702. c)

Sammes, P. G.; Street, L. J J. Chem. Soc., Chem. Commun. 1983,666

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Chapt

5. a) Griffin, G . W.; Padwa, A. in 'Photochcmisw of Heterocyclic

Compounds', ed. Buchart, 0. Wiley, New York, 1976, Chapter 2, p. 41

b) Das, P. K.; Griffin, G. W. Photochem 1985,27,3 17.

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Hoffmann, P.; Luthardt, H. Chem. Ber. 1968, 101, 3861.

a) de March, P.; Huisgen, R. J. Am. Chem. Soc. 1982,104,4952, b)

L'esperance, R. P.; Ford, T. M.; Jones, M. J. Am. Chem. Soc. 1988,110,

209.

Hojo, M.; Aihara, H.; Suginohara, Y.; Sakata, K.; Naklamura, S.;

Murakami, C.; Hosomi, A. J. Org. Chem, 1997,62, 86 10.

Takai, K.; Kaihara, H.; Higashiura, K.; Ikeda, N. J. Org. Chem. 1997,62,

8612

a) Ibata, T.; Motoyama, T.; Hamaguchi, M. Bull. Chem. Soc. Jpn. 1976,

49,2298. b) Ibata, 'r'.; Toyoda, J. Chem. Left. 1983, 1453. c) Ibata, T.;

Toyoda, J.; Sawada, M.; Tamakii, T. J. Chem. Soc., Chem. Commun.

1986,1266.

a) Padwa, A,; Carter, S. I).; Nimmesgem J. Org. Chem. 1985,50,4417.

b) Padwa, A.; Carter. S . P.; Nimrnesgem J. Am. Chem. Soc. 1988,110,

2894. c) Padwa, A,; Fryxell, G. E.; Zhi, L. J. Org. Chem. 1988,53,2875.

a) Ibata, T.; Toyoda, ./. Bull. Chem. Soc. Jpn. 1986, 59,2489. b) Toyoda,

J.; Ibata. T.; l'amura. 1-1.: Ogaiva, K.; Nishino, T.; Takebayashi, M. Bull.

Chem. Soc. Jpn. 1985, 58, 22 12. c) Ibata, T.; Toyoda, J. Bull. Chem. Soc.

Jpn. 1985, 58, 1787, d) I'amura, H.; Ibata, T.; Ogawa, K. Bull. Chem.

Soc. Jpn. 1984. 5 7, 926. e) Ibata, T.; Toyoda, J. Chem. Lett. 1983, 1453.

f ) Ibata, T.; Jitsuhiro, K.: Tsubokura Y. Bull. Chem. Soc. Jpn. 1981,54,240.

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g) Hamaguchi. M.; Ibata, T. (:hem. Lett. 1976, 287. h) Ibata, T.;

Motoyama, 'I'.; Hamaguchi, M. Bull. Chem. Soc. Jpn. 1976, 49,2298.

i) Ibaia, T. Chem. Len. 1976,233. j) Veda, K.; Ibata, T.; Takebayashi, M.

Bull. Chem. Soc. Jpn. 1972, 45,2779.

14. Gillon, A,; Ovadia, 13.; Kapon. M.; Bien, S. Tetrahedron, 1982,38, 1477.

15. Kinder, F. R.; Bair, K. W. J. Org. Chem. 1994,59,6965.

16. Padwa, A,; Chinn, R. L.; Hornbuckle, S. F.; Zhi, L. Tetrahedron Lett.

1989, 30. 301

17. Padwa, A,; Precedo.. I,.; Semones, M. A. J. Org. Chem. 1999,64,4079.

18. Nair, V.; Sheela, K. C:.; Radhakrishnan, K. V.; Rath, N. P. Tetrahedron

Lett. 1998. 39. 5627.

19. Sheela, K. C. Ph. D. Thesis, Cochin University of Science and

Technology, Kerala, :2000

20. Nair, V; Sheela, K. C.; Sethumadhavan, D.; Bindu, S.; Rath, N. P.;

Eigendorf, G. K. Synlett 2000,272.