NOVEL REARRANGEMENT OF CHLOROMETHYLVINYLSILANES INTO ALLYLSILANES. STEREOSELECTIVE SYNTHESIS OF METALLATED ALLYLSILANES FROM 1-ALKYNES

Article abstract of DOI:10.1016/S0040-4020(01)86652-7

Regio and stereoselective hydralumination of 1-(chloromethyldimethylsilyl)-1-alkyne with diisobutylaluminium hydride (DIBAH) affords (Z)-1-(chloromethyldimethylsilyl)-1-(diisobutylalumino)-1-alkene.Treatment of the aluminium-substituted vinylsilane with 3 equivalents of methyllithium affords (E)-1-(trimethylsilyl)-2-lithio-2-alkene as a sole product.Reaction of aluminium-substituted vinylsilane with trimethylaluminium in refluxing heptane produces a mixture of (E)-1-trimethyl-silyl-2-alumino-2-alkene and 2-trimethylsilyl-1-alkene.Reaction of 1-(chloromethyldimethylsilyl)-1-alkyne with triisobutylaluminium gives 2-(isobutyldimethylsilyl)-1-alkene exclusively.Reactions of the lithiated allylsilane with several electrophiles give the corresponding carbometallated products, allylsilanes bearing alkyl, allyl, vinyl, or alkoxycarbonyl groups.Protodesilylation of 3-(trimethylsilylmethyl)-1,3-decadiene gives 3-methylene-1-decene selectively.Reaction of trialkylaluminium with trimethylsilylethyne gives bistrimethylsilylated diene by successive addition of silylethyne to the aluminium reagent; in contrast, chloromethyldimethylsilylethyne gives the mono-adduct regio and stereoselectively.