Merck

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
RESUMO

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.

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Sigma-Aldrich
Rhodium, powder, 99.95% trace metals basis
Rhodium, foil, not light tested, 25x25mm, thickness 0.00025mm, permanent polyester support, 99.9%
Rhodium, foil, 25x25mm, thickness 0.1mm, as rolled, 99.9%
Rhodium, foil, not light tested, 25x25mm, thickness 0.0005mm, permanent polyester support, 99.85%
Rhodium, microfoil, disks, 10mm, thinness 0.1μm, specific density 124μg/cm2, permanent mylar 3.5μm support, 99.9%
Rhodium, foil, not light tested, 50x50mm, thickness 0.006mm, as rolled, 99.9%
Rhodium, foil, 12mm disks, thickness 0.5mm, as rolled, 99.9%
Rhodium, foil, not light tested, 25x25mm, thickness 0.012mm, as rolled, 99.9%
Rhodium, foil, not light tested, 25x25mm, thickness 0.00075mm, permanent polyester support, 99.85%
Rhodium, microfoil, disks, 25mm, thinness 0.25μm, specific density 310μg/cm2, permanent mylar 3.5μm support, 99.99%
Rhodium, microfoil, disks, 10mm, thinness 0.25μm, specific density 310μg/cm2, permanent mylar 3.5μm support, 99.99%
Rhodium, foil, light tested, 25x25mm, thickness 0.05mm, as rolled, 99.9%
Rhodium, foil, 25x25mm, thickness 0.15mm, as rolled, 99.9%
Rhodium, microfoil, disks, 10mm, thinness 0.50μm, specific density 620μg/cm2, permanent mylar 3.5μm support, 99.99%
Rhodium, foil, light tested, 25x25mm, thickness 0.05mm, as rolled, x-ray quality, 99.9%
Rhodium, foil, light tested, 15x15mm, thickness 0.05mm, as rolled, 99.9%
Rhodium, foil, not light tested, 25x25mm, thickness 0.006mm, as rolled, 99.9%
Rhodium, wire reel, 0.05m, diameter 0.25mm, hard, 99.9%
Rhodium, foil, light tested, 25x25mm, thickness 0.075mm, as rolled, 99.9%
Rhodium, microfoil, disks, 25mm, thinness 0.1μm, specific density 124μg/cm2, permanent mylar 3.5μm support, 99.9%
Rhodium, foil, not light tested, 25x25mm, thickness 0.001mm, permanent polyester support, 99.85%
Rhodium, foil, not light tested, 50x50mm, thickness 0.00075mm, permanent polyester support, 99.85%
Rhodium, foil, 25x25mm, thickness 0.125mm, as rolled, 99.9%
Rhodium, wire reel, 0.05m, diameter 0.5mm, as drawn, 99.9%
Rhodium, foil, not light tested, 50x50mm, thickness 0.001mm, permanent polyester support, 99.85%
Rhodium, wire reel, 0.2m, diameter 0.25mm, hard, 99.9%
Rhodium, wire reel, 0.2m, diameter 0.5mm, as drawn, 99.9%
Rhodium, wire reel, 0.5m, diameter 0.12mm, as drawn, 99.9%
Rhodium, wire reel, 0.5m, diameter 0.25mm, hard, 99.9%
Rhodium, foil, not light tested, 50x50mm, thickness 0.00025mm, permanent polyester support, 99.9%