SILICON CARBON UNSATURATED-COMPOUNDS .38. NICKEL-CATALYZED REACTIONS OF DISILANYL-SUBSTITUTED ENYNES WITH DIPHENYLACETYLENE

(E)-1-(Methyldiphenylsilyl)-4-pentamethyldisilanyl-, (E)-1-(methyldiphenylsilyl)-4-(1-phenyltetramethyldisilanyl)-, (E)-1-(methyldiphenylsilyl)-4-(2-phenyltetramethyldisilanyl)-, (E)-1,4-bis(pentamethyldisilanyl)-, (E)-1,4-bis(1-phenyltetramethyldisilanyl)-, and (E)-4-(methyldiphenylsilyl)-1-(1-phenyltetramethyldisilanyl)but-1-en-3-yne (1-6) were prepared, and their nickel-catalyzed reactions with diphenylacetylene were investigated. The reaction of 1a and 4 with diphenylacetylene in the presence of a catalytic amount of dichlorobis(triethylphosphine)nickel(II) at 200-degrees-C for 20 h in a sealed glass tube gave 6-[trans-(methyldiphenylsilyl)ethenyl]-1,1,4,4,5-pentamethyl-2,3-diphenyl-1,4-disilacyclohexa-2,5-diene (7a) and 1,1,4,4,5-pentamethyl-6-[trans-(pentamethyldisilanyl)ethenyl]-2,3-diphenyl-1,4-disilacyclohexa-2,5-diene (9). The reaction of 2 and 5 under the same conditions afforded 1,1,4,4-tetramethyl-6-[trans-(methyldiphenylsilyl)ethenyl]-2,3,5-triphenyl-6-[trans-(1-phenyltetramethyldisilanyl)ethenyl]-1,4-disilacyclohexa-2,5-diene. Compound 3 also reacted with diphenylacetylene under the same conditions, affording 8 as the sole volatile product. Treatment of (E)-4-[1-(deuteriomethyl)tetramethyldisilanyl]-1-(methyldiphenylsilyl)but-1-en-3-yne with diphenylacetylene in the presence of the nickel catalyst gave a mixture consisting of products in which a deuteriomethyl group was distributed onto a ring sp2 carbon atom and two ring silicon atoms. The reaction of 6 with diphenylacetylene under the same conditions, however, afforded no volatile products.