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Enantioselective total synthesis of guanacastepene N using an uncommon 7-endo Heck cyclization as a pivotal step.

ABSTRACT: A convergent, enantioselective total synthesis of (+)-guanacastepene N was developed that features a 7-endo Heck cyclization as the key step. In the course of this synthesis, short syntheses of the enantiomerically pure cyclopentenone and cyclohexene building blocks 5 and 6, which constitute A and C ring fragments of guanacastepene N, were developed. These fragments were linked by a challenging conjugate addition reaction that also generated the C11 quaternary carbon stereocenter. Regioselective 7-endo Heck cyclization gave rise to a tricyclic intermediate, which was elaborated to complete the first total synthesis of guanacastepene N and the second enantioselective total synthesis of a guanacastepene natural product.

SUBMITTER: Iimura S

PROVIDER: S-EPMC3804222 | biostudies-literature | 2006 Oct

REPOSITORIES: biostudies-literature

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Enantioselective total synthesis of guanacastepene N using an uncommon 7-endo Heck cyclization as a pivotal step.

Iimura Shin S Overman Larry E LE Paulini Ralph R Zakarian Armen A

Journal of the American Chemical Society 20061001 40

A convergent, enantioselective total synthesis of (+)-guanacastepene N was developed that features a 7-endo Heck cyclization as the key step. In the course of this synthesis, short syntheses of the enantiomerically pure cyclopentenone and cyclohexene building blocks 5 and 6, which constitute A and C ring fragments of guanacastepene N, were developed. These fragments were linked by a challenging conjugate addition reaction that also generated the C11 quaternary carbon stereocenter. Regioselective ...[more]

PMID: 17017789

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