RING-OPENING REACTIONS OF ALPHA-STANNYL EPOXIDES WITH METAL-HYDRIDES AND ORGANOCUPRATES

alpha-Epoxyorganostannanes are attacked by metal hydride reagents (DIBAL-H, LiAlH4, REDAL) and Me2CuLi at the carbon atom proximal to the tin atom and directly at the tin atom. For example, tributyl(epoxyethyl)stannane (5) reacts with DIBAL-H to give a mixture of 2-(tributylstannyl)ethanol (7) and tributyltin hydride. Reaction of 5 with Me2CuLi affords predominantly 2-(tributylstannyl)propan-1-ol (8) and some Bu3SnMe. Similarly, 3-(tributylstannyl)oxiranemethanol (10) reacts with REDAL and Me2CuLi to provide products of nucleophilic attack at C-3. Cleavage occurs with inversion of stereochemistry. Tributyl(3,4-epoxybutyl)stannane (21) reacts with LiAlH4 to give secondary alcohol 22 as the sole product.