- Enantioselective hydroformylation of N-vinyl carboxamides, allyl carbamates, and allyl ethers using chiral diazaphospholane ligands
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Rhodium complexes of diazaphospholane ligands catalyze the asymmetric hydroformylation of N-vinyl carboxamides, allyl ethers, and allyl carbamates; products include 1,2- and 1,3-aminoaldehydes and 1,3-alkoxyaldehydes. Using glass pressure bottles, short reaction times (generally less than 6 h), and low catalyst loading (commonly 0.5 mol %), 20 substrates are successfully converted to chiral aldehydes with useful regioselectivity and high enantioselectivity (up to 99% ee). Chiral Roche aldehyde is obtained with 97% ee from the hydroformylation of allyl silyl ethers. Commonly difficult substrates such as 1,1- and 1,2-disubstituted alkenes undergo effective hydroformylation with 89-97% ee and complete conversion for six examples. Palladium-catalyzed aerobic oxidative amination of allyl benzyl ether followed by enantioselective hydroformylation yields the β3-aminoaldehyde with 74% ee.
- McDonald, Richard I.,Wong, Gene W.,Neupane, Ram P.,Stahl, Shannon S.,Landis, Clark R.
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supporting information; experimental part
p. 14027 - 14029
(2011/01/04)
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