Organic chemistry. Rh-catalyzed C-C bond cleavage by transfer hydroformylation.

Organic chemistry. Rh-catalyzed C-C bond cleavage by transfer hydroformylation.

Science (New York, N.Y.) (2015-01-03)

Stephen K Murphy, Jung-Woo Park, Faben A Cruz, Vy M Dong

RÉSUMÉ

The dehydroformylation of aldehydes to generate olefins occurs during the biosynthesis of various sterols, including cholesterol in humans. Here, we implement a synthetic version that features the transfer of a formyl group and hydride from an aldehyde substrate to a strained olefin acceptor. A Rhodium (Xantphos)(benzoate) catalyst activates aldehyde carbon-hydrogen (C-H) bonds with high chemoselectivity to trigger carbon-carbon (C-C) bond cleavage and generate olefins at low loadings (0.3 to 2 mole percent) and temperatures (22° to 80°C). This mild protocol can be applied to various natural products and was used to achieve a three-step synthesis of (+)-yohimbenone. A study of the mechanism reveals that the benzoate counterion acts as a proton shuttle to enable transfer hydroformylation.

MATÉRIAUX

Référence du produit

Marque

Description du produit

204218

Sigma-Aldrich

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