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Rh-Catalyzed rearrangement of vinylcyclopropane to 1,3-diene units attached to N-heterocycles.

ABSTRACT: Dienes embedded in quinolizidine and indolizidine structures can be prepared in four steps from cyclic nitrones and bicyclopropylidene. The key intermediates ?-spirocyclopropanated N-heterocyclic ketones, generated via a domino 1,3-dipolar cycloaddition/thermal rearrangement sequence, were converted by Wittig methylenation to the corresponding vinylcyclopropanes (VCPs), which underwent rearrangement to 1,3-dienes in the presence of the Wilkinson Rh(I) complex under microwave heating. The previously unexplored Rh(I)-catalyzed opening of the VCP moiety embedded in an azapolycyclic system occurs at high temperature (110-130 °C) to afford the corresponding 1,3-dienes in moderate yield (34-53%).

SUBMITTER: Cordero FM

PROVIDER: S-EPMC3063054 | biostudies-literature | 2011 Mar

REPOSITORIES: biostudies-literature

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Rh-Catalyzed rearrangement of vinylcyclopropane to 1,3-diene units attached to N-heterocycles.

Cordero Franca M FM Vurchio Carolina C Cicchi Stefano S de Meijere Armin A Brandi Alberto A

Beilstein journal of organic chemistry 20110309

Dienes embedded in quinolizidine and indolizidine structures can be prepared in four steps from cyclic nitrones and bicyclopropylidene. The key intermediates α-spirocyclopropanated N-heterocyclic ketones, generated via a domino 1,3-dipolar cycloaddition/thermal rearrangement sequence, were converted by Wittig methylenation to the corresponding vinylcyclopropanes (VCPs), which underwent rearrangement to 1,3-dienes in the presence of the Wilkinson Rh(I) complex under microwave heating. The previou ...[more]

PMID: 21448251

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