6. C. A. Tolman, J. Am. Chem. Soc., 92, 2953 (1970). 7. A. J. Deeming and B. L. Shaw, J. Chem. Soc., A, 1802 (1969). 8. R. F. Heck and D. S. Breslow, J. Am. Chem. Soc., 83, 1097 (1961). 9. K. Masters, Homogeneous Catalysis by Transition Metals [Russian translation], Mir, Mos-

cow (1983), p. 124. i0. C. A. Tolman, J. Am. Chem. Soc., 92, 2956 (1970). ii. M. F. McGuiggan, D. H. Doghty, and L. H. Pignolet, J. Organomet. Chem., 185, 241 (1980). 12. M. Aresta, C. F. Nobile, M. Rossi, and A. Sacco, J. Chem. Soc., D, 781 (1971). 13. W. C. Child and H. Adkins, J. Am. Chem. Soc., 47, 798 (1925).

CYCLOPENTADIENYL DERIVATIVES OF MAGNESIUM AND SODIUM IN CROSS-COMBINATION

REACTION WITH ALLYL COMPOUNDS CATALYZED BY PdCOMPLEXES

U. M. Dzhemilev, A. G. Ibragimov, UDC 542.97:547.514.722 E. V. Gribanova, and L. M. Khalilov

In a continuation of our study on cross-combination of organomagnesium reagents with 0-, N-, and S-containing allyl compounds [i], we studied the reaction of cyclopentadienylmagnesi- um bromide, bis(cyclopentadienyl)magnesium, and also cyclopentadienylsodium with allyl ethers and esters, allyl sulfides, quaternized allylamines, and allyl sulfones, catalyzed by transi- tion-metal complexes, to develop effective methods for preparing difficultly available allyl- cyclopentadienes. According to [2-4], the noncatalyzed cross-combination of cyclopentadienyl- magnesium chloride and cyclopentadienylsodium with aliyl halides leads to the formation of a mixture of isomeric allylcyclopentadienes in yields not higher than 40%.

Salts of Cu, Ti, Zr, Fe, Co, Ni, Cr, and Pd were tested as catalysts in these reactions; Pd(acac) 2 and PdCI2, activated by Ph3P, have the highest catalytic activity. We used a model reaction of cross-combination of diallyl ether with cyclopentadienylmagnesium bromide to study the influence of the nature of the solvent and reaction conditions on the yield of the com- bination products. The maximal yields of allylcyclopentadienes were obtained in THF and Et20 at 40~ at a reaction duration of 2 h. A mixture of i- and 2-allylcyclopentadienes (I) and (II) is thus formed in a ratio of ~85:15 in a quantitative yield. This reaction does not pro- ceed in the absence of palladium catalyst

] • , 9 / " • . [Pd]--pb~p CpMgBr* [Pd]'PhsP a_ _~ v , +

( j x h 0 ' 4 ] ~ ) ~ . / ~ , 8 . 5

(II) (1)

* C p M g B r =

MgBr

The ratio and yield of (I) and (II) vary noticeably, depending on the nature of the li- gand in the catalyst. For example, the overall yield of (I) and (II) decreases from 96 to 55% in the series of PPh~, (C6HI~O)3P, (C6H~3)3As, and (PhO) 3P=O ligand--activators, and the con- tent of (II) in these experiments increases to 60% (Table i). The structure of the allyl compounds thus practically does not influence the composition of allylcyclopentadienes (Table 2).

Under the conditions studied, because of the equivalency of the carbon atoms of the cy- clopentadienyl anion, probably 5-allylcyclopentadiene is first formed containing a mobile H atom at C s. The subsequent migration of H and the shift of the double bonds in the cyclopent- adienyl ring leads to a mixture of (I) and (II):

Institute of Chemistry, Bashkir Branch, Academy of Sciences of the USSR, Ufa. Translated from izvestiyaAkademiiNauk SSSR, Seriya Khimicheskaya, No. ii, pp. 2562-2566, November, 1985. Original article submitted June 20, 1984.

2374 0568-5230/85/3411-2374'$09.50 �9 1986 Plenum Publishing Corporation

TABLE i. Influence of Nature of Ligand--Activator on Over- all Yield and Ratio of (I) and (II) [Pd(acac) 2:Ln (/~_)~O

Ph3P

(C~HI3)~As

CpMgBr = 1:1:35:40, THF, 40~ 2 h]

-- Overa l l Reac t i on pro- ducts

Act ivator yield, .~176 (I) (II) . , Act ivator

96 85 t5 (PhO) 3P=O

(i-C3HT.0)~P 85 70 30

63 65 35

React ion pro- Overa l l du.cct~ . yield, %] r a) (n)

55 40 ,60

20. 75 25

H H H H H

(i) (n)

The mixtures of allylcyclopentadienes (I) and (II) obtained are not in equilibrium, as indicated by the change in their compositionwith time: Irrespective of the composition of the mixture obtained, after 3-5 days the ratio of (I) and (II) becomes ~i:i in each case. Un- der the experimental conditions, it was impossible to detect the formation of 5-allylcyclopent- adiene in noticeable amounts. According to [5-7], in a mixture of substituted cyclopentadi- enes the content of the isomer with the substituent at the 5 position is not more than 5%.

The structure of (I) and (II) was confirmed by spectral methods. In the PMR spectrum of a mixture of (I) and (II) there are two multiplets of the methylene protons. The signal at 2.98 ppm belongs to (I), and the weak-field signal at 3.10 ppm corresponds to isomer (II).

In the Z3C NMR spectrum of an equilibrium mixture of (I) and (II), the difference in the chemical shifts of the signals of the isomers reaches ~2 ppm. The presence of a substituent at C z in (I) leads to descreening of C 5 due to the 8 effect of the allyl group, while screen- ing of C 5 of isomer (II) is comparable to that by the corresponding C atom in unsubstituted cyclopentadiene (41.6 ppm) [8].

With increase in the allyl radical, the yield of the combination products decreases in- appreciably. For example, bringing 1.6-octadienyl ethers and esters into the reaction leads to an equilibrium mixture (~i:i) of i- and 2-(2,7-octadienyl)cyclopentadienes (III) and (IV) in an overall yield of 54-78%:

CpMgBr [Pd]--Ph3P

R x - / % / ' \ / " ~ +

X = O , CO~;~R=CIt~ Et, Bu, Ph.

3 2 7 9 I t 1 3 "

~U IL/ '~ ,A/ ' , , J (m) \ / 6 8 !0 l~

/ ' , , . ~ / ' \ / % , ( iv )

U

Similar results were obtained in a study of the cross-combination reaction of cyclopent- adienylmagnesium bromide with heptyl, nonyl, and benzyl halides in THF in the presence of a Cu(acac)2-PPhz catalyst. In each case, a mixture of i- and 2-alkylcyclopentadienes is obtained in high yields:

U ti (V), .(VII), (IX) [Cu]_phsp . - -

C p M g B r - ~ RX 68-84% > "~- ' " 11, R (vi), (v,i,/, (x), \ /

X el, Br, I; R = C7H15 (V), (VI);CgH19 (VII), (VIII); PhCH~. (IX), (X)

2375

TABLE 2. Influence of Structure of Allyl Compound on Overall Yield and Composition of Cross-Combination Products [Pd(acac) 2: PhsP: //\,XR :CpMrBr = 1:1:35:40, THF, 2 h

( .~\_hO

, ~ - - O A c

//\CO2_/%

I //\Co2_/~

AUyl compound

96

90

88

74

.68

[e:action )roducts

( i ) . / i i )

85 i5

98 2

98 2

92 - 8

98 2

AUyl compound

( / : \ _ h s

/~\--SO~Ph + "

(//\_),N(Me)I-

+ //\ NEtt(Me)I-

.~, Reaction ~,~, products

O "~ (i) (Ii)

66 ( 2

62 9~ 2

56 9~ 2

50 98 2

In reactions with allyl ethers and esters, allyl sulfides, and allyl sulfones, cyclopent- adienylsodium gives lower yields (22-34%) of the corresponding i- and 2-allylcyclopentadienes (I) and (II):

Na 0), (n)

+ X ---- O, S, SOn, COs, (CHs)2NI-;R ---- Bu, Ph, . ~ " x _ , P h _ . ~ . . , .

To compare the reactivity of symmetric and asymmetric organomagnesium reagents in the cross-combination process, we studied the reaction of bis(cyclopentadienyl)magnesium and cy- clopentadienylbutylmagnesium with the above allyl compounds by the action of palladium cat- alysts. As a result, allylcyclopentadienes (I) and (II) are obtained in high yields. In ex- periments with cyclopentadienylbutylmagnesium, besides (I) and (II), l-heptene is also formed, (I):(II):(XI) ~ 1:1:2. The reaction proceeds to give satisfactory yields in the presence of a Ph3P-activated bimetallic catalyst Pd(acac)2--Cu(acac)2:

Mg > (i),+ .i~

~xR

(xl)

X = O, S, SO,, COn, (CH~)~N*I-; R = Bu, Ph, CH~-CHCH2

The catalyzed cross-combination of cyclopentadienyl derivatives of magnesium and sodium with functional N-, O-, and S-containing ally ! compounds, allyl and aryl halides is an effec- tive method for synthesizing i- and 2-substituted cyclopentadienes in high yields.

EXPERImeNTAL

In the investigation, allyl compounds Of ~99% purity were used. Cyclopentadienylmagnesium bromide, cyclopentadienylsodium, bis(cycl0pentadienyl)magnesium, and cyclopentadienylbutyl- magnesium were obtained according to [3, 4, 9, i0]. The reaction products were analyzed on a Chrom-5 chromatograph, using a flame-ionization detector and a 1200 • 3 mm column with PEG-6000 (15% on Chromaton N-AW). The PMR spectra were recorded on a Tesla BS-467 spectro- meter in CC14, with HMDS as the internal standard; the 13C NMR spectra on a JeoI-FX-90Q spectrometer with broad band suppressions of protons in CDCI3, using TMS as the standard. The IR spectra were recorded on a UR-20 spectrophotometer !in thin layer). The mass spectra

2376

were run on an MX-13-06 apparatus, with an ionizing-electron energy of 70 eV at an ionization chamber temperature of 200~

General Procedure of Cross-Combination of Cyclopentadienyl Derivatives of Magnesium (Sodium) with Allyl Compounds

A 40-mmole portion of the corresponding cyclopentadienyl derivative of magnesium or sodi- um was added, with stirring in an argon current, to a solution of 0.30 g (i mmole) of Pd(ac- ac) 2, 0.262 g (i mmole) of Ph3P, and 35 mmoles of allyl compound cooled to --5~ and the solu- tion was allowed to stand at this temperature for ~i0 min. The solution was transferred into a thermostated glass reactor and heated for 2 h at 40~ (combination with alkyl and aryl hal- ides was carried Out at O~ At the end of the reaction, the catalyzate was decomposed by a saturated NH4CI solution, extracted by ether, washed with NaHC03, and water to a neutral reaction, and dried over MgS04. After distillation of the solvent, the residue was fraction- ated in vacuum. The products obtained had the following physical and spectral characteristics.

i- and 2-Allylcyclopentadienes (I):(II) ~ i:i, bp 60-61~ (55 mm), nD2~ 1.4806. IR spec- trum (v, cm-1): 920, i000, 1530, 3080. PMR spectrum (~, ppm): 2.33-2.92 m (2H, CH2), 2.98 m for (I), 3.10 m for (If) (2H at C5), 4.67-5.18 m (3H, CH2----CH), 5.33-6.33 m (3H, --CH=, Cp). M + m/z 106. ~3C NMR (6, ppm) for (I): 35.35 t (C6), 43.26 t (C) s, 115.34 t (C8), 127.26 d (C2), 131.08 d (C3), 134.56 d (C4), 137.05 d (C7), 147.32 s (C~). 13NMR (6, ppm) for (II): 34.46 t (C6), 41.35 t (C 5) 115 34 t (C s) 126.78 d (CI), 132,46 d (C3), 133.80 d (C 4) 136.42 d (C 7) 144.92 s (C2).

i- and 2-(2,7-Octadienyl)cvclopentadienes (III):(IV) = i:i, bp 64-65~ (i mm), n 2o 1.4882. IR spectrum (v, cm-~: 920, 975, i000, 3085. PMR spectrum (~, ppm): 1.20-1.70Dm (2H, CH=), 1.78-2.30 m (4H, CH2--C<), 2.70-2.90 m (2H at C6), 2.92-3.25 m (2H at C5], 4.67-6.42 (8Holef). M+ m/z 174. ~3C NM~R (~, ppm) for (III): 28.74 t (C~~ ~, 31.88 t (C9)~ 33.25 t (CI~), 34.11 t (C6), 43.21 t (CS), 114.40 t (C13), 126.71 d (C4), 128.71 d (C7), 130.85 d (C3), 131.37 d (CS), 132.43 d (C=), 138.77 d (C!~), 145.81 s (CI). ~SC NMR (6, ppm) for (IV): 28.74 t (C~~ 31.94 t (C9), 33.25 t (C~), 33.72 t (C6), 41.26 t (CS), 114.40 t (C~3), 126.26 d (C4), 128.04 d (C7), 131.12 d (C~), 133.68 d (C3), 134.63 d (C~), 138.77 d (C~2), 148.48 s (c~).

i- and 2-Heptylcyclopentadienes (V):(VI) ~ i:i, bp 67-68~ (2 mm), nD 2~ 1.4698. PMR spec- trum (6, ppm): 0.87 t (3H, CH3), 1.30 m (10H, CH2), 2.12-2.50 m (2H at C6), 2.75 m for (V), 2.83 m, for (VI): (2H at C5), 5.67-6.33 m (3Holef). ~ m/z 164. 13C NMR spectrum (6, ppm) for (V): 14.15 q (C~2), 22.80 t (C~), 29.32 t (C9), 29.56 t (CB), 29.89 t (C7), 30.83 t (C6), 31.97 t (C~~ 43.24 t (C5), 126.19 d (C2), 130.23 d (C3), 132.48 d (C4), 150.07 s (C~). ~3C NMR (6, ppm) for (VI): 14.15 q (C~2), 22.80 t (C~), 29.00 t (C~), 29.32 t (C~), 29.60 t (CS), 29.97 t (C~), 31.97 t (C~~ 41.18 t (C~), 125.61 d (C~), 133.45 d (C~), 134.84 d (C~), 147.41 s (C~).

i-- and 2-Nonylcyclopentadienes (VII):(VIII) ~ i:i, bp 84-85~ (i mm), nD =~ 1.4765. PMR spectrum (~, ppm): 0.86 t (3H, CH~), 1.03-1.67 m (14H, CH=), 1.28-2.50 m (2H, at C6), 2.75 m for (VII), 2.83 m for (VIII) (2H, at C~), 5.83-6.40 m (3Holef). M§ m/z 192. I~C NMR (~, ppm) for (VII): 14.13 q (C ~) 22 76 t (CZS), 29.43 t (C z~) 29.65 t C 9 C ~~ 29.67 t (C a ) 28.86 , �9 , ~ , ,

t (C~), 30.80 t (C~), 31.99 t (C~Z), 43.24 t (CS), 126.15 d (C~), 130.23 d (C~), 132.46 d (C4), 150.12 s (C~). I~C NMR (~, ppm), for (VIII) 14.13 q (C~4), 22.76 t (C~S), 28.98 t (C~), 29.43 t (C~I), 29.63 t (C ~, C~~ 29.67 t (CS), 29.95 t (CV), 41.18 t (C~), 125.59 d (C~), 133.45 d (C4), 134.84 d (C~), 147.41 s (C~).

i- and 2-Benzylcyclopentadienes (IX):(X) m i:i, bp 76-77~ (i mm) ,nD z~ 1.5433. PMR spec- trum (6, ppm): 2.75 m for (IX), 2.88 m for (X) (2H at C~), 3.53-3.73 m (2H, CH~Ph), 5.83-6.37 m (3H ~#), 7.13 m (5H, Harom). M+ m/z, 156 ~C NMR (6 ppm) for (IX): 37 34 t (C ~) 42.89 t

5 ~ i0 ' " '

(C), 125.80 d (C), 127.26 d (C~), 128.00 d (C~), 128.56 d (C~), 131.18 d (C~), 134.47 d (C4), 140.69 s (C~), 147.99 s (C~). ~SC NMR (~, ppm) for (X): 36.30 t (C~), 41.07 (C~), 128.80 d (C =, C~~ 128.17 d (CS), 128.69 (C~), 132.46 d (C~), 133.72 d (C4), 139.69 s (C~), 145.70 s (C=).

CONCLUSIONS

An effective method was developed for synthesizing allylcyclopentadienes by cross-combi- nation of cyclopentadienyl derivatives of magnesium and sodium with 0-, N-, and C-containing allyl compounds in the presence of palladium complexes. The substituted cyclopentadienes ob-

2377

tained comprise equilibrium mixtures of isomers, containing I- and 2-allylcyclopentadienes in a I:I ratio.

LITERATURE CITED

i. A. G. Ibragimov, D. L. Minsker, R. A. Saraev, and U. M. Dzhemilev, Izv. Akad. Nauk SSSR, Se~. Khim., 2333 (1983).

2. U. S. Patent No. 3105839 (1963); Chem. Abstr., 60, 2804 (1964). '3. U. S. Patent No. 3287395 (1966); Chem. Abstr., 66, 29354 (1967). 4. R. Riemschneider, E. Hoerner, and F. Herzel, Monatsh., 778 (1961). 5. V. A. Mironov, A. P. Ivanov, Ya. M. Kimel'fel'd, and A. A. Akhrem, Izv. Akad. Nauk SSSR,

Ser. Khim., 376 (1973). 6. V. A. Mironov, T. M. Radeeva, and S. A. Yankovskii, Zh. Org. Khim., 12, 992 (1976). 7. V. A. Mironov, V. T. Luk'yanov, and A. A. Vernadskii, Zh. Org. Khim., 20, 69 (1984). 8. J. B. Stofhers, Carbon-13 NMR Spectroscopy, Academic Press, New York (1972), p. 82. 9. H. O. House, R. A. Latkam, and G. M. Whitesides, J. Org. Chem., 32, 2481 (1967).

i0. G. Wilkinson, F. A. Cotton, and J. M. Birmingham, J. Inorg. Nucl. Chem., 2, 95 (1956).

ORGANOBORON COI~OUNDS.

COIg{UNICATION 420. NEW THERMAL REARRANGEMENT IN THE SERIES OF CYCLIC

TETRACOORDINATED BORON COMPOUNDS

V. A. Dorokhov, M. N. Bochkareva, UDC 541.11:542.952.1:547.1'127 and B. M. Mikhailov*

Isomeric bicyclic chelate-type compounds (I)-(III), containing a tetracoordinated boron atom in one of the six-membered rings, have already been synthesized from 2-aminopyridine and isocyanates. The reaction of N-organyl-N'-(2-pyridyl)ureas with organoboranes leads to (I) and (II) [i, 2], while heterocycles (III) are formed as a result of the addition of 2-diorgan- ylborylaminopyridines (DBAP) to isocyanates [3, 4].

R e

R'R"N- ~ ^ 0 ~

B

R / \R / \ - ( i ) R , R

(Ii)

O~/N\) R'--N N R "

\ / B

/ \ R R

(ni)

In the chelate rings of (I) and (II), one and the same ligand (a substituted pyridylurea) is coordinated with the B atom in a different way. It was found that when (I) (R" = H) is heated, it smoothly isomerizes into (II). The process probably proceeds with opening of the boron-containing ring and a 1,3-migration of the R2B group [2].

In the present work, we report on a new thermal rearrangement -- conversion of diorganyl- boryl-l-(N-organyl)carbamoylpyrid-2-one-iminates (IIIa-f) into N-diorganylboryl-2-(N-organyl)- carbamoylaminopyridinates (IIa-f):

A (III) ---+ (II)

R : B u , R ' = o - C H 3 C s H 4 , R " - ~ H (a); R = P r , R ' = P h , R " : H (b); R = P r , R ' = ---- o-CH3CsH4, I:{" = Ph (e); R - - Pr, R ' = R" = Ph (d); R ~ Bu, R ' : M e , R" = H (e); R : R ' - - R" ----- P h ( f ) .

*Deceased.

N. D~ Zelinskii Institute of Orgaric Chemistry, Academy of Sciences of the USSR, Moscow. Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. ii, pp. 2567-2570, November, 1985. Original article submitted June 8, 1984.

2378 0568-5230/85/3411-2378509.50 �9 1986 Plenum Publishing Corporation