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Synlett 2005(4): 658-660  
DOI: 10.1055/s-2005-863714
LETTER
© Georg Thieme Verlag Stuttgart · New York

Nickel-Catalyzed Cross-Coupling of Diphenylphosphine with Vinyl Bromides and Chlorides as a Route to Diphenylvinylphosphines

Mstilsav O. Shulyupin, Evgeniy A. Chirkov, Marina A. Kazankova*, Irina P. Beletskaya
Department of Chemistry, Moscow State University (MSU), Leninskie Gory 1, Building 3, 119992 Moscow, Russia
Fax: +7(095)9328846; e-Mail: kazank@org.chem.msu.ru;
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Publication History

Received 15 December 2004
Publication Date:
22 February 2005 (online)

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Abstract

An efficient nickel-catalyzed reaction for the phosphination of vinyl bromides and chlorides was developed. The procedure uses a combination of up to 1 mol% of nickel acetylacetonate, triethylamine and dimethylformamide as a solvent. The double bond geometry of the vinyl halides was retained under the reaction conditions.

Key words

cross-coupling - phosphorus - nickel - alkenylphosphines

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General Procedure (for Compounds 1-5).
A Schlenk flask was charged with 5 mmol of alkenyl bromide, 5 mmol of Et3N, 5 mmol of diphenylphosphine, 5 mL of DMF and 1 mol% of Ni(acac)2. The reaction mixture was stirred for specified period at maintained temperature (Table [2] ). To this mixture 20 mL of H2O and 20 mL of benzene were added after cooling. The benzene phase was separated, washed with 10 mL of H2O, and dried under MgSO4. Then, 20 mg of dimethylglyoxime were added to the benzene solution. After 1 h the solution was passed through short layer of silica gel and evaporated in vacuum. The crude product was then distilled under reduced pressure.
E -(2-Ethoxyvinyl)diphenylphosphine ( 1): yield 90%, colorless oil, bp 120-124 °C/4 Torr. 1H NMR (400 MHz, CDCl3): δ = 1.25-1.28 (t, 3 ), 3.82-3.88 (q, 2 ), 5.32-5.35 (d, 1 , J HH = 14 Hz), 6.86-6.92 (dd, 1 , J HH = 14 Hz, J PH = 9 Hz), 7.21-7.40 (m, 10 ). 13C NMR (100.6 MHz, CDCl3): δ = 14.51 (-H3), 65.24 (-O-CH2), 97.63, 128.01, 128.21, 132.20, 159. 31P{H} NMR (162.6 MHz, CDCl3): δ = -18.0. Anal. Calcd for C 16H17OP (%): C, 74.99; H, 6.69. Found: C, 75.02; H, 6.52.
Z -(1-Methylpropenyl)diphenylphosphine ( 2): yield 90%, colorless oil, bp 110 °C/3 Torr. 1H NMR (400 MHz, CDCl3): δ = 1.72 (dt, 3 H, =(P)CH3, J PH = 1.0 Hz, J HH = 7.4 Hz), 1.77 (d, 3 H, =(P)CH3, J PH = 6.7 Hz), 5.95 (m, -H), 7.32 (m, 10 H, C6H5). 13C NMR (100.6 MHz, CDCl3): δ = 137.09 (d, =C-P, J P = 32.1 Hz), 133.22 (d, C=C-P, J P = 19.8 Hz), 136.51 (d, J P = 10.7 Hz, ipso), 128.65 (m, 6H5), 15.00 (d, CH3-C=C-P, J P = 15.2 Hz), 15.00 [d, C=C(PPh2)CH3, J P = 39.6 Hz]. 31P{H} NMR (162.6 MHz, CDCl3): δ = 5.9. Anal. Calcd for C16H17P (%): C, 79.98; H, 7.13; P, 12.89. Found: C, 79.35; H, 6.96; P, 12.83.
General Procedure (for Compounds 6, 8, 9).
A Schlenk flask was charged with 2.5 mmol of alkenyl chloride, 8 mmol of Et3N, 2 mmol of diphenylphosphine, 3 mL of DMF, and 2 mol% of Ni(PPh3)2Cl2. The solution was stirred for specified period at maintained temperature. To this solution 20 mL of H2O and 20 mL of benzene were added after cooling. The benzene phase was separated, washed with 10 mL of H2O and dried under MgSO4. Then, 20 mg of dimethylglyoxime were added to benzene solution and after 1 h the solution was passed through short layer of silica gel and evaporated in vacuum. The crude product was then purified by column chromatography (Al2O3, THF).
1,1-Bis(diphenylphosphino)-2-( p -methoxyphenyl)ethane ( 8): yield 93%, mp 127 °C. 1H NMR (400 MHz, CDCl3): δ = 3.68 (s, 3 ), 6.74 (d, 1 H), 7.03-7.39 (m, 25 ). 13C NMR (100.6 MHz, CDCl3): δ = 55.10 (d, O-CH3, J = 9.0 Hz), 113.25 (d, J = 4.5 Hz), 127.68, 128.27 (dd), 130.0 (t), 131.29 (t), 132.39 [dd, Ph2P-C(PPh2)=C, J = 33.6 Hz, J = 48.8 Hz], 133.83 (d, J = 21.4 Hz), 134.27 (d, J = 19.8 Hz), 135.84 (dd, J = 6.1 Hz, J = 9.2 Hz), 136.47 (d, J = 15.0 Hz), 152.79 (dd, J = 9.0 Hz, J = 23.0 Hz), 159.48. 31P{H} NMR (162.6 MHz, CDCl3): δ = -3.8 (d, J = 1.5 Hz), -12.0 (d, J = 1.5 Hz). Anal. Calcd for C 33H28P2O (%): C, 78.80; H, 5.62. Found: C, 77.49; H, 5.79.