Some epoxide ring-opening reactions of αβ-epoxysilanes

Abstract

Epoxide ring-opening of 1,2-epoxy-1-trimethylsilylcyclohexane (3) has given a range of the 2-substituted 2-trimethylsilylcyclohexanols (4; X = H, OH, OMe, OCH₂CHCH₂, Br, I, SCN) in which attack by nucleophile has occurred at the carbon α to silicon. The products (4) have been transformed into a number of functionalised silanes, including the silyl-episulphide (9). Other epoxides which have been less extensively studied are the conformationally biased epoxysilanes (10) and (11), the eight-membered ring epoxysilanes (17) and (21) and the two stereoisomeric 2,3-epoxy-3-trimethylsilylpentanes (26) and (29). Epoxide ring-opened adducts were obtained after treatment with H⁺–MeOH in all cases except for compound (17), where the bicyclic alcohol (18) was formed by a transannular reaction.