3 Phosphine Oxides and Related Compounds

BY B. J. WALKER

1 Introduction.

Phosphine oxide-based olefin synthesis is being increasingly used

and is the method of choice in a number of recent syntheses of

natural products and related compounds.

2 Preparation of Acyclic Phosphine Oxides

Bis(trimethylsily1)peroxide (1) can be used to produce phosphine

oxides stereospecifically from either phosphines (with retention) o r

phosphine sulphides (with inversion). A variety of organoelement

substituted pentadienes, including the phosphine oxides ( 2 ) and ( 3 ) .

have been prepared by the reaction of the appropriate organoelement

halide with pentadienyllithium.’

ketones to give trienes and ( 3 ) forms complexes with P d , Fe and Ni.3

Both the mono-(l) and di-(5) phosphine oxides are formed in

The anion of ( 3 ) reacts with

reactions of sodium glycolates with dimethyl(chloromethy1)phosphine

oxides, the proportions of the products depending on the reaction

conditions.4

prepared from the corresponding phosphine.

The allene(tetraph0sphine) chalcogenides (6) have been

3 Preparation of Cyclic Phosphine Oxides

Attempts to prepare the oxide (7) of 1.2.3-triphenylphosphirene were

unsuccessful, €I although the corresponding sulphide ( 8 ) was prepared

by reaction of the phosphirene with sulphur and N-methylimidazole.

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84

Me,SiOOSi Me,

( 1 )

L L

L i +

Organophosphorus Chemistty

PhP *

Ph2 P SiMt, II

0 It

M c2 P CH,O ( C H, InO R2

( 4 ) $ = H ( 5 ) R = CH,P(O)Me,

n s 2 - 6

(Ph,P(X 1 I2C=C=C( P(X)Ph2I2

( 6 ) X = 0 , S , Se

Ph

Ph

( 7 ) X = 0

( S I X = S

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3: Phosphine Oxides and Related Compounds 85

The phosphine oxide (10). the first reported example of a phosphorus

analogue of an unsaturated 6-lactam, has been obtained from the

complexed phosphine ( 9 ) . ' Z-Phenylphospholino[ 3,4-d] tropone-2-oxide

(12) has been synthesized using the McCormack reaction of the diene

(11) to generate the basic carbon skeleton (Scheme 1).8 A number of

novel phosphine oxide structures (3. 13) have been prepared during

the synthesis of 1,1,6,6-tetramethyldibenzo[b,e]phospha~ulol~dene

9 (14) *

The compounds (16) and (18) have been obtained by air oxidation

of (15) and (17). respectively, and provide the first isolated

examples of polycyclophosphine oxides. lo

4 Structure and Physical Aspects

The mechanism of the reaction of dialkylphosphine oxides (19) with

carbon tetrachloride has been investigated using 31P n.m. r.

spectroscopy."

the disproportionation of (19) to give dialkylphosphinic acid and

dialkylphosphine, this reaction is catalyzed by acid chlorides which

are the initially formed products.

The reaction pathway is complex, but a key step is

In an attempt to estimate the value for the anomeric effect

contributing to the axial preference for the diphenylphosphinoyl

group in ( 2 0 ) . the conformational preference of the phosphinoyl

group in a variety of cyclohexyldiphenylphosphine oxides ( 21)12 and

in the oxides (22) and ( ~ 3 ) ~ ~ have been investigated by n.m.r.

spectroscopy. The anomeric effect of 3.74 kcal mol-I obtained is

the largest yet measured. Consideration of X-ray structural data

for (22) and (20) and a study of solvent effects on the

axial-equatorial equilibrium for (20) do not provide a clear picture

of why the axial isomer predominates, although a number of different

factors are certainly operating. l3

The fluorescence properties of a range of diarylalkylphosphine

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86 Organophosphorus Chemistry

. . . I l l I

H

Iv Br , , a p C p h H' 0

Reagents : i PhPCL2 Cu ( 1 1 1 s t e a r a t e hexane ; ii , H20 ; i t i ~ ' ' 3 ~ ; i v , T F A

Cl

Scheme 1

( 1 3 ) X = O (14) X = lone pair

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3: Phosphine Oxides and Related Compounds 87

0 II

2 R,PH

(191

O* PPh, I

But

+

+ I I PBu'

But

( 1 8 )

+ R,PH

Rbi PPh,

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88 Organophosphorus Chemistry

oxides have been investigated. l4

fluorescence unless one of the phosphorus substituents is itself

fluorescent,and even in these cases (except that of the biphenyl

substituent) the quantum yield of fluorescence in the phosphine

oxide is less than that of the substituent hydrocarbon.

These compounds exhibit only weak

- X-ray diffraction studies have been reported for the stable 1:l adduct of triphenylphosphine oxide with pentaf luorophenol15 and for

two modifications of triphenylphosphine oxide itself. Careful

analysis of the latter data indicates that appreciable internal

rotations of the phenyl groups occur even in the crystal form. The

gas-phase basicity of a variety of trialkylphosphine oxides has been

investigated both experimentally (by ion cyclotron resonance

spectroscopy) and theoreti~a1ly.l~

5 Reactions at Phosphorus

Phosphine oxides are reduced to phosphines in excellent yield under

mild conditions by a 3:l mixture of LiA1H4 with CeC13.18

reagent is claimed to be far superior to LiAlH4 alone and is

especially useful for sterically hindered oxides. Unfortunately the

one optically active phosphine oxide investigated gave a

predominantly racemic product. The addition of sodium borohydride

to the LiA1H4-CeC13 reagent provided a convenient synthesis of

phosphine bOKaneS ( 2 4 ) from the corresponding phosphine oxides.

The 1-hydroxyalkylphosphine oxides (25) and (26) have been obtained

by reaction of diphenylphosphine oxide with diacetyl and ethyl

pyruvate, respectively. 2o

oxide,addition to the second carbonyl group of diacetyl does not

The

Even in the presence of excess phosphine

occur.

Interest in p-rr bonded phosphorus continues and studies

involving phosphine oxides include the dimerization of the

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3: Phosphine Oxides and Related Compounds

0

Ph- P -R2 II

I R’

0 I t

Me Ph,PC( OH )COMe

LIAIHL, NaBH4, YH3 2 * Ph-P-R C e C I 3 i

R’

0 R \ I I

2 ,,P=C-PR2R3 - R

( 2 7 )

s+p//s

0 IJ

Me Ph2PC( 0 H 1 COO H

0

89

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90 Organophosphorus Chemistry

phosphaalkyne (27) to give (29).21

confirmed by X--ray crystallography and its formation obviously

involves P-P oxygen transfer (probably via (28)) rather than simple

dimerization. The chemistry of the sterically-stabilized dithio-

metaphosphonate analogue (30) has been reported.

The stcucture of (29) was

22

6 Reactions at the Side-Chain

The chemistry and synthetic applications of phosphono carbanions

have been reviewed. 23

The [4+2]-cycloaddition reactions of thioxo-(31, X=S) and

seleno-(31, X=Se) phospholes with triazolindiones and maleic

anhydride derivatives have been inve~tigated.~~

water in the reactions with triazolindiones leads to the exclusive

formation of phosphine oxide adducts from both (31, X = S ) and (31,

x=se). Thermolysis of the adducts (32) and photolysis of the

adducts (33) leads to [4+l]-cycloreversion in each case to give,

respectively, PhP=S and PhP=Se as shown by alcohol-trapping

reactions. The cycloaddition of 2-azaallyl anions (e.9. 34) to

diphenylvinylphosphine oxide to give, e.g. (35) and (36) has been

~eported.'~ Intramolecular reaction of the carbene (37) (generated

from the corresponding diazoalkane) gives mainly the

cyclooctatetraene ( 3 8 ) together with a small amount of the

semibullvalene (39). 26

at the tellurium atom to give the cations ( 4 0 ) . which form phosphine

and dimethyltelluride on treatment with methyllithi~m.'~

The presence of

Phosphine tellurides are readily methylated

The extensive use of phosphine oxide carbanions in alkene

synthesis continues. Full details of stereoselective routes to the

erthro- and threo-2-hydroxyalkylphosphine oxide precursors of

alkenes, their conversion to the corresponding (z)- and (E)-alkenes and explanations of the stereoselectivities have appeared. 28

Similarly,'a full report of the synthesis of (E) - and

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3: Phosphine Oxides and Related Compounds 91

Ph Se p//

Me ( 3 3 )

Li 0 I I e- ..A

Ph,PCH=CH, + ph N Ph

( 3 4 )

0

PPh, It

PhQPh ( 3 5 )

H

+ o II

Ph yPPh;%,, NCH,Ph H

. C- PPh, ' I t

0 (37)

+

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92 Organophosphorus Chemistry

(g)-y,h-unsaturated ketals (41) using this method has been

published. 29

carboxylic acids is provided by the highly stereoselective reaction

of ethyldiphenylphosphine oxide anion with cyclohexene oxide to give

(42) almost exclusively.30 Oxidation of the ketone (43) followed by

Baeyer-Villiger rearrangement gave the lactone (44)

regioselectively, hydrolysis of which gave the acid (45) directly

(Scheme 2). All four racemic diastereomers of the substituted

3-alkyl-4-hydroxybutenes (Lg. 47) have been prepared by

decomposition of the appropriate 2-hydroxyalkylphosphine oxide

diastereomer ( L g . 46).31

(E)-homoallylic alcohols (50). y-hydroxyketones (52) and

cyclopropylketones (53) from the key phosphine oxide intermediate

(48) .32

followed by base treatment gives (50). Direct treatment of (48)

with base gives (51) Ph2P(0) transfer from carbon to oxygen

followed by formation of either (52) o r (53) depending on the

reaction conditions (Scheme 3 ) . The route involving reduction of

2-ketoalkylphosphine oxides has also been used to synthesise the

(E)-alkene (54) .33 During this investigation the sensitivity of the

stereochemistry of reduction (and hence of the olefin formed) to the

nature of the reducing agent was noted. The intermediates (55)

(erythro, leading to (g)-alkene) and (57) (threo, leading to

(E)-alkene) are respectively generated selectively by direct

reaction of alkyldiphenylphosphine oxide anion with aldehydes and by

reduction of 2-ketoalkylphosphine oxides (56). 34 The reduction

route to threo-(57) is frequently more stereoselective than the

direct route to erythro-(55). Warren has now shown that replacement

of the diphenylphosphinyl group by dibenzophosphole in the

2-ketoalkylphosphine oxides allows highly stereoselective generation

of erythro-2-hydroxyalkylphosphine oxides by reduction of (58) with

A potentially general route to (Z)-unsaturated

New routes are available to

Reduction of (48) to the 2-hydroxyalkylphosphine oxide ( 4 9 )

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3: Phosphine Oxides and Related Compounds 93

M e 1 + - R3P=Te R3P-TeMe I

( 4 0 )

H 0 II

Ph,PCH,CH, --+

H' Me Me

( L 2 I (43)

H Me (44)

Reagents: i BuLi ; i i J 00 j i i i , NaOCl A c O H ; I V RCOOOH

Scheme 2

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94 Organophosphorus Chemistry

(46) (47)

( 4 8 )

... I l l I

( 4 9 1 ( 5 0 )

(51 )

( 5 2 )

oc

Reagents : i , NaBH,& , M e O H ; i i , N a H , T H F ; i i i , K O R ; i v , KOH,H20,EtOH;v,ButOK,

B ~ ~ O H

Scheme 3

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3: Phosphine Oxides and Related Compounds 95

NaBH4-CeC13,as well as generation of the threo-isomer through the

use of borohydride alone. A convenient alternative and

stereospecific route to diastereomeric 2-hydroxyalkylphosphine

oxides is available from the reaction o f diphenylphosphide with each

pure isomer of the appropriate epoxide followed by oxidation.

Unfortunately in many cases base-catalyzed decomposition of the pure

erythro-phosphine oxide leads not to pure (Z)-alkene, but to a

mixture with (E)-alkene probably due to equillibration of ervthro-

with threo-phosphine oxide y& dissociation to aldehyde and anion

(59).

ervthro-2-hydroxyalkylphosphine oxide ( 6 0 ) . derived from

dibenzophosphole, is much more stereoselective and the use of DBU in

dimethyl sulphoxide solution as the base gives an excellent yield of

>99% (Z)-stilbene; presumably because the "small-ring" effect

increases the rate of oxaphosphetan formation to the extent that

reversion to aldehyde cannot compete.

It is now reported35 that the similar decomposition of

Phosphine oxide-based olefination has been increasingly used as

a synthetic method. The phosphine oxide ( 6 2 ) . required f o r a

synthesis of B-milbemycin (64). has been prepared as a mixture of

isomers by an SN2' reaction of the lactone ( 6 1 ) with

diphenylphosphide anion followed by oxidation. 3 6

of the olefination reaction of ( E J - ( 6 2 ) , under a variety of

conditions,revealed that the required (E)-stereochemistry and

highest yield were provided by generation of the anion using

NaN(TMS)2 followed by reaction with aldehyde ( 6 3 ) (Scheme 4). A

milbemycin-avermectin hybrid has been synthesized by coupling the

intact northern segment ( 6 5 ) with a southern segment using phosphine

oxide-based olef ination, followed by cyclization. 37 The anion of

- cis-crotyldiphenylphosphine oxide ( 6 6 ) has been used to introduce

the (B,Z)-diene system stereospecifically in synthesis of the

goldinonolactone fragment ( 6 7 ) of the elfamycin antibiotic^.^^

An investigation

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96 Organophosphorus Chemistry

Ar OMe Me

0

'"Y R'

HOAR2

( 5 5 )

0 1 1 Ph

ph2p+ 4- Ph -' H

0 0 II II

( 5 6 ) ( 5 7 )

0 II -

Ph2PCHPh + PhCHO

0 11 Ph

P h 2 P \ f i H -oA- H

Ph

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3: Phosphine Oxides and Related Compounds 97

aYH p”/o , P h

4-- Ph HO

H

DEU - Me2S0

% Me

OMe ( 6 1 ) ( 6 2 )

0 I I

Ph,PCH,

+ ( Z ) - i s o m e r

OH

( 6 4 )

Reagents : I , Ph2P-; 1 1 , H202; III , CH2N2 ; I V , NaN(TMS13 ; v , d v t ,cycliration

CHO OTBS

(63)

Scheme 4

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98 Organophosphorus Chemistry

0

Me -CH ,b’,h,

-

OT BS

0 It -

Ph,PCHOMe

Me

& ZH { 0 Me)2

Me H

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3: Phosphine Oxides and Related Compounds 99

reaction of the ketone (68) with (methoxymethy1)diphenylphosphine

oxide anion is highly stereoselective to give (Z)-alkene (69). 39

25-Ketovitamin D3 has been synthesized by the olefination of (70)

with the phosphine oxide anion (71).40

The reactions of 2-[1,3]dithianyldiphenylphosphine oxide (72)

and sulphide (73) anions with carbonyl compounds have been

i n ~ e s t i g a t e d . ~ ~

aldehydes and ketones to give alkenes, while phosphine sulphide

anions (73) do not react with ketones and give only poor yields of

alkenes with aldehydes. This difference in reactivity is explained

in terms of the oxaphosphetane and thiaphosphetane intermediates

involved. It is worth noting that diarylalkylphosphine imides (74)

can be metallated in a similar way to their phosphine oxide

analogues. 42

at carbon to give (75) (the best yields are obtained in the presence

of N,N,N,'N'-tetramethylenediamine) and react with aryl nitriles to

give the enamines (76) which in turn can be hydrolysed to the

B-ketophosphine oxides' (77) (Scheme 5).

The phosphine oxide anions (72) react with both

The anions of (74) can be alkylated regioselectively

7 Phosphine Oxide Complexes and Extractants

Platinum complexes ( L g . 78) containing diphenylphosphine oxide

ligands are reported to be effective as hydroformulation

catalysts.43 Unlike their 0, S and Se analogues, transition metal

complexes of phosphine tellurides are unknown. The photolysis of

the chromium group metal hexacarbonyls in the presence of phosphine

tellurides is reported to give (79) as the first examples of these

complexes, 44

The cycloadditions of oxetanes with isocyanates to give

oxazin-2-ones (80) are catalyzed by the tin halide-phosphine oxide

complex (81) .45 Th.e synthesis of ( 8 2 ) , a new type of uranium

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100 Organophosphorus Chemistry

O* PPh, 1

( 7 2 ) X = O (73) x - s

(751

(7 7) R e a g e n t s : i, L D A , T H F J - 3 O 0 C ; i i J R 2 X , - 7 O 0 C ; i i i , A r C N , - 7 O 0 C ; i v , H O ; v , H30+

2

Scheme 5

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3: Phosphine Oxides and Related Compounds

Ph Ph ,o-P * PLO, ’ \ /

Ph2 I Et

M(CO), + R,P=Te % M(CO)S(R3PTel

(79)

M r C r , M o , W ; R = B u t

PYR Bu2Sn12 . Ph,PO O ~ N R ’

0 (81 1

(801

101

UI,( Ph ,PO l2

( 8 2 1

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102

tetraiodide complex, has been reported.46

Organophosphorus Chemistry

1.

2.

3.

4.

5.

6. 7.

8.

9.

10.

11. 12.

13.

14. 15.

16.

17.

18.

19.

20 * 21 *

22 *

23.

24.

25.

26.

27. 28.

29.

30. 31, 32.

REFERENCES L. Wozniak, J. Kowalski, and J. Chojnowski, Tetrahedron Lett., 1985, 26, 4965. T. Kauffmann and K7R. Gaydoul, Tetrahedron Lett., 1985, 26, 4065. T. Kauffmann and K-rR. Gaydoul, Tetrahedron Letr., 1985, 26, 4071. S. Varbanov, 1. Dencheva, G. Nedecheva, and G. Borisov, Phosphorus Sulfur, 1985, 25, 307. H. Schmidbaur and T. Pollock, Angew. Chem., Int. Ed. EnRl., 1986, 25, 348. A. Marinetti and F. Mathey. J. Am. Chem. SOC., 1985, 107, 4700. A. Marinetti, J. Fischer, and F. Hathey, J. Am. Chem. SOC., 1985, 107, 5001. H. Kato, S. Nomura, H. Kobayashi, and T. Hiwa, Chem. Lett., 1986, 281. C.H. Chen, J.J. Doney, J.L. Fox, and H.R. Luss, J. OrR. Chem., 1985, SO, 2914. M. Baudler, M. Hichels, H. Pieroth, and J. Hahn, Angew. Chem., Int. Ed. Engl., 1986, a, 471. G. Aksnes and P. Majewski, Phosphorus Sulfur, 1986, 26, 261. E. Juaristi, 8.A. L%pez-Ni%ez, R.S. Glass, A. Petson, R.O. Hutchins, and J.P. Stercho, J. O w . Chem., 1986, 5 l , 1357. E. Juaristi, L. Valle, B.A. Valenzuela, and H.A. Aguilar, J- Am. Chem. SOC., 1986, 108, 2000. J. Bourson and L. Oliveros, Phosphorus Sulfur, 1986, 26, 75. T. Gramstad, S. Husebye, and K. Maartmann-Hoe, Acta Chem. Scand., 1986, m. 26. C.P. Brook, W.B. Schweizer, and J.D. Dunitz, J. Am. Chem. SOC., 1985, 107. 6964. J.C. Bollinger, R. Houriet, C.W. Kern, D. Perret, J. Weber, and T. Yvernault, J. Am. Chem. Soc., 1985, 107, 5352. T. Imamoto, T. Takeyama, and T. Kusumoto, Chem. Lett., 1985, 1491. T. Imamoto, T. Kusumoto, N. Suzuki, and K. Sato, J. Am. Chem. e., 1985, 107, 5301. J.A. Mukroyannidis, Phosphorus Sulfur , 1985, 25 , 39. H. Keller, G. Maas, and H. Regitz, Tetrahedron Lett., 1986, 27, 1903. J. Navech, H. Revel, R. Kraemer, and S. Hathieu, Phosphorus Sulfur, 1986, 26, 83. 2. Liu, Huaxue Shiji, 1985, L, 84 (Chem. Abstr., 1985, 103, 196132). R. Hussong, H. Heydt, and M. Regitz, Phosphorus Sulfur, 1986, 25, 201.

Kuffmann, H. Ahlers, KrJ. Echsler, H. Schulz, and HrJ. Tilhard, Chem. Ber., 1985, 118, 4496. M. Bohshar, H. Heydt, and M. Regitz, Tetrahedron, 1986, 42 , 1815. 8. Kuhn and H. Schumann, Phosphorus Sulfur, 1986, 26, 199. A.D. Buss and S. Warren, J. Chem. SOC.. Perkin Trans.1, 1985, 2307. C.A. Cornish and S. Warrkn, J. Chem. S O C . , Perkin Trans.1, 1985, 2585. D. Levin and S. Warren, Tetrahedron Lett., 1986, 27, 2265. A.B. HcElroy and S. Warren, Tetrahedron Lett., 1985, 26, 5709. P. Wallace' and S. Warren, Tetrahedron Lett., 1985, 26, 5713.

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ober

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39/9

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3: Phosphine Oxides and Related Compounds 103

33.

34. 35.

36.

37.

38.

39.

40.

41.

42.

43.

44.

45.

46.

J. Kallmerten and M.D. Wittman, Tetrahedron LeB., 1986, 22, 2443. J. Elliot and S. Warren, Tetrahedron Lett., 1986, 27, 645. T.G. Roberts and G. Whitham, J. Chem. SOC., Perkin Trans.1, 1985, 1953. S.R. Schow, J.D. Bloom, A . S . Thompson, K.N. Winzenberg, and A . B . Smith, 111, J. Am. Chem. SOC., 1986, 108. 2662. A . B . Smith, 111 and A . S . Thompson, Tetrahedron Lett., 1985, &, 4283. R.E. Dolle and K.C. Nicolaou, J. Chem. SOC.. Chem. Comun., 1985, 1016. M.P. Bosch, F. Camps, J. Coll, A . Guerro, T. Tatsuoka, and J. Meinwald, J. Org. Chem., 1986, 5 l , 773. J.L. WascareEas, A. Mouri”n, and L. Castedo, J. Org. Chem., 1986, 51, 1269. E. Juaristi, B. Gordillo, and L. Valle, Tetrahedron, 1986, 42. 1963. J. Barluenga, F. Lopez, and F. Palacios, J. Chem. Res.(S), 1985, 211; (MI 2541. P.W.N.M. Van Leeuwen, C.F. Roobeek, R.L. Wife, and J.H.G. Frijns, J. Chem. Sac. . Chem. Cormrmn., 1986, 31. N. Kuhn, H. Schumann, and G. Wolmershauser, J. Chem. SOC., Chem. Comun.. 1985, 1595. A . Baba, I. Shibata, M. Fujiwara, and H. Matsuda, Tetrahedron m., 1985, 26, 5167. J.G.H. du Preez and B. Zeelie, J. Chem. SOC., Chem. Commun., 1986, 743.

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200

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bs.r

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39/9

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View Online