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Stereochemical control in the reduction of 2-chromanols.

ABSTRACT: [reaction: see text] Reduction of C5-substituted 2-hydroxychromans selectively provides 2,4-cis-chromans using large silane reductants and 2,4-trans-chromans using the smaller silane PhSiH(3). The stereochemical outcome has been rationalized on the basis of a Curtin-Hammett kinetic situation arising from hydride delivery to two different conformations of an intermediate oxocarbenium ion. This method provides a powerful way to control the relative stereochemistry of these substructures which are prevalent in bioactive natural products.

SUBMITTER: Li K

PROVIDER: S-EPMC2538801 | biostudies-literature | 2006 Oct

REPOSITORIES: biostudies-literature

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Stereochemical control in the reduction of 2-chromanols.

Li Kelin K Vanka Kumar K Thompson Ward H WH Tunge Jon A JA

Organic letters 20061001 21

[reaction: see text] Reduction of C5-substituted 2-hydroxychromans selectively provides 2,4-cis-chromans using large silane reductants and 2,4-trans-chromans using the smaller silane PhSiH(3). The stereochemical outcome has been rationalized on the basis of a Curtin-Hammett kinetic situation arising from hydride delivery to two different conformations of an intermediate oxocarbenium ion. This method provides a powerful way to control the relative stereochemistry of these substructures which are ...[more]

PMID: 17020284

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