Efficient syntheses of functionalized piperidines through extremely regioselective Rh-catalyzed cyclohydrocarbonylation of amido-ω,ω′-dienes
摘要:
The highly regioselective cyclohydrocarbonylation of 4-amido-1,6-heptadienes catalyzed by Rh-BIPHEPHOS complex gives functionalized piperidines quantitatively, which serve as versatile intermediates for the syntheses of a variety of piperidine and quinolizidine alkaloids. Reaction of 3-Boc-amino-1,5-hexadiene affords the corresponding dehydropiperidine-aldehyde exclusively via site and regioselective hydroformylation. Possible mechanisms for these reactions are proposed. (C) 1998 Elsevier Science Ltd. All rights reserved.