Enantioselective Total Synthesis and Determination of the Absolute Configuration of the 4,6,8,10,16,18‐Hexamethyldocosane from Antitrogus parvulus

The absolute and relative configuration of the hexamethyldocosane ( 1 ) isolated from the cuticula of Antitrogus parvulus was determined based on the total synthesis of both diastereomers 1a and 1b in enantiomerically pure form. The synthesis demonstrates the utility of the o ‐DPPB‐directed and copper‐mediated allylic syn ‐substitution reaction with Grignard reagents for iterative deoxypropionate construction ( o ‐DPPB = ortho ‐diphenylphosphanylbenzoyl). Additionally, the synthetic power of copper catalyzed sp 3 –sp 3 cross coupling reactions by twofold employment for building block construction and as the final fragment coupling step in the course of a convergent total synthesis is shown. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)