A highly diastereoselective approach to tetrahydrofurans via [3+2] cycloadditions of silylmethyl-substituted cyclopropanes with aldehydes and ketones

An efficient and highly diastereoselective synthesis of highly substituted tetrahydrofurans from the reaction of a vicinal t-butyldiphenylsilylmethyl-substituted cyclopropyl diester with aldehydes and ketones has been developed. The 2,5-cis-disubstitution predominates over the 2,5-trans-disubstitution by as much as 12:1. The reaction with cyclic ketones generates spiro-fused tetrahydrofurans in good yields.