Application of the Chloro Ketal Claisen Reaction to the Total Synthesis of Squalene

Abstract

A short, highly stereoselective (over 97%) synthesis of all-trans squalene is described. Starting with succinaldehyde, a tetraenedichlorodione having the complete squalene skeleton with the four internal trans olefinic bonds has been developed in four steps involving a sequence of two double Claisen rearrangements. Three simple operations convert this intermediate into squalene.