Palladium(II)-catalyzed highly stereoselective sandwich-type triple cyclization reaction of 1,5-bisallenes and 2,3-allenoic acids

摘要

(Figure Presented) Triple-decker sandwich: A sandwich-type triple cyclization of two molecules of 2,3-allenoic acid and one molecule of 1,5-bisallene in the presence of a palladium catalyst with excellent stereoselectivity has been developed. The diallyl-substituted cis products may easily be transformed to fused tetracyclic compounds with a 12-membered ring (see scheme). Based on the result of optically active 2,3-allenoic acids, a possible catalytic cycle has been proposed.