A convergent synthesis of (+)-pancratistatin based on intramolecular electrophilic aromatic substitution

Abstract

A convergent formal synthesis of (+)-pancratistatin ( 1) is reported. Specifically, an optically active adduct of piperonyl bromide and acetonated conduritol A was converted to a late-stage intermediate from the Danishefsky-Lee synthesis of 1. The carbon skeleton was established via intramolecular electrophilic aromatic substitution within the piperonylated conduritol. Some competitive cationic rearrangement was observed in this operation, being dependent on the degree to which a 2-substituent in the piperonyl domain favors attack ipso to the piperonyl benzylic carbon.