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Highly diastereoselective chelation-controlled additions to ?-silyloxy ketones.

ABSTRACT: The polar Felkin-Anh, Cornforth-Evans, and Cram-chelation models predict that the addition of organometallic reagents to silyl-protected ?-hydroxy ketones proceeds via a nonchelation pathway to give anti-diol addition products. This prediction has held true for the vast majority of additions reported in the literature, and few methods for chelation-controlled additions of organometallic reagents to silyl-protected ?-hydroxy ketones have been introduced. Herein, we present a general and highly diastereoselective method for the addition of dialkylzincs and (E)-di-, (E)-tri-, and (Z)-disubstituted vinylzinc reagents to ?-silyloxy ketones using alkyl zinc halide Lewis acids, RZnX, to give chelation-controlled products (dr ?18:1). The compatibility of organozinc reagents with other functional groups makes this method potentially very useful in complex molecule synthesis.

SUBMITTER: Stanton GR

PROVIDER: S-EPMC3112462 | biostudies-literature | 2011 May

REPOSITORIES: biostudies-literature

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Highly diastereoselective chelation-controlled additions to α-silyloxy ketones.

Stanton Gretchen R GR Koz Gamze G Walsh Patrick J PJ

Journal of the American Chemical Society 20110502 20

The polar Felkin-Anh, Cornforth-Evans, and Cram-chelation models predict that the addition of organometallic reagents to silyl-protected α-hydroxy ketones proceeds via a nonchelation pathway to give anti-diol addition products. This prediction has held true for the vast majority of additions reported in the literature, and few methods for chelation-controlled additions of organometallic reagents to silyl-protected α-hydroxy ketones have been introduced. Herein, we present a general and highly di ...[more]

PMID: 21534530

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