REACTIONS OF PENTAFLUOROPHENYLTRIMETHYLSILANE AND CYANOMETHYLTRIMETHYLSILANE WITH CARBONYL COMPOUNDS CATALYZED BY CYANIDE ANIONS

Article abstract of DOI:10.1016/S0022-328X(00)81786-6

Treatment of pentafluorophenyltrimethylsilane (I) and cyanomethyltrimethylsilane (II) with enolizable ketones in the presence of a catalytic amount of potassium cyanide-18-crown-6 complex gave the corresponding trimethylsilyl enol ethers.The same dehydrogenative silylation of acetylacetone and benzoylacetone with silane I was extended to the preparation of 2,4-bis(trimethylsiloxy)-1,3-pentadiene and 1-phenyl-1,3-bis(trimethylsiloxy)-1,3-butadiene, respectively.The dehydrogenative silylation of acetylacetone and benzoylacetone with dimethylbis(pentafluorophenyl)silane u nder the same conditions affords novel heterocycles 5-methylene-2,6-dioxa-1-silacyclohex-3-enes.In the reaction studied the silylating ability of the silanes increases in the order Me3SiCN ca.Me2Si(CN)2 < Me3SiCH2CN < Me3SiC6F5 ca.Me2Si(C6F5)2.On the other hand, potassium cyanide-18-crown-6 complex catalyzed the addition of silane I or II to a carbonyl group of non-enolizable compounds such as benzaldehyde, crotonaldehyde, and methyl(triethylgermyl)ketene.