Enantioselective Synthesis of the Unsymmetrical Bis(lactone) (-)-3E,6R,9E,12S,14R)-Colletol Induced by Chiral Sulfoxides and an Approach to (+)-Colletodiol by Asymmetric Hydroxylation of an α,β-Hydroxy Lactone

摘要

A general synthetic strategy towards the two bis(lactones) (-)-colletol (1) and (+)-colletodiol (2) is described. A common intermediate in this synthesis is the 6-membered hydroxy lactone (+)-(3R,5R)-3-hydroxy-5-hexanolide (6), readily prepared by stereoselective reduction of (+)-(SR)-methyl 3,5-dioxo-6-(p-toluenesulfinyl)hexanoate (7). Stereoselective hydroxylation of this hydroxy lactone has allowed efficient access to (+)-colletodiol (2).