Enantio- and Diastereoselective Allylmetalations:  An Easy and Efficient Access to the AB Spiroketal of Spongistatin

Abstract

A unique combination of highly enantio- and diastereoselective allylmetalations and a one-pot “desacetalization/spiroketalization” have been employed to synthesize the AB spiroketal fragment (C1−C13) of spongistatin in 15 steps and in excellent diastereoselectivity