Diastereoselective Synthesis of Optically Active C2-Substituted Spiro[4.5]decanes : Two Key Intermediates for Spirovetivane Sesquiterpenes

Abstract

We investigated the stereoselective construction of the C2 stereogenic center of the spiro[4.5]decane skeleton present in the spirovetivanes, spirolaurane, and spiroaxanes, and succeeded in synthesizing 2α- and 2β-substituted 6-spiro[4.5]decanones with diastereoselectivity by employing n-Bu₃-SnH-mediated spiroannulation of the alkylmercury chloride, and Pd(II)-mediated spiroannulation followed by catalytic hydrogenation of the resulting unsaturated ester, respectively.