Synthesis of dienic α-ketoesters by Friedel-Crafts reaction of ethyl oxalyl chloride with tricarbonyl iron complexes of E- and Z- substituted acyclic dienes

Abstract

Tricarbonyl iron coordinated acyclic dienes react with ethyl oxalyl chloride|AlCl 3 to E- dienic α-ketoester complexes. This allows a rapid synthesis of such dienes by decomplexation. Not only E- alkyl-substituted but also Z-substituted dienes can be functionalized this way, whereas Z-dienic α-ketoester complexes can be obtained by acid catalyzed E → Z isomerization.