Rhodium-catalyzed 1,4-addition of alkenylzirconocene chlorides to electron deficient alkenes

The 1,4-conjugated addition of alkenylzirconocene chloride complexes to alpha,beta-enones, alpha,beta-enoic acid esters, and alpha,beta-enoic acid amides can be efficiently achieved by the use of [RhCl(cod)](2) catalyst. A high diastereoselectivity (95% yield, 90% de) was obtained through the reaction of alpha,beta-enoic acid amide derived from Oppolzer's sultam and 2-butenoyl chloride, while the use of Evans' chiral oxazolidinone as a chiral auxiliary in place of Oppolzer's sultam, gave a poor diastereoselectivity (98% yield, 26% de). (C) 2003 Elsevier Ltd. All rights reserved.