Enantioselective addition of nitromethane to α-keto esters catalyzed by copper(<scp>ii</scp>)–iminopyridine complexes
作者:Gonzalo Blay、Victor Hernández-Olmos、José R. Pedro
DOI:10.1039/b716446g
日期:——
The coppercomplex of a chiral iminopyridine easily prepared from (R)-(-)-fenchone and picolylamine catalyzes the enantioselective Henry (nitroaldol) reaction between nitromethane and alpha-keto esters. Good yields and modest to good enantioselectivities are obtained for a wide range of alpha-keto esters, bearing aromatic, alkyl or alkenyl groups attached to the ketone carbonyl group.
Asymmetricnitroaldolreaction of α-ketoesters was explored using a guanidine–thioureabifunctionalorganocatalyst at temperatures below the freezing point of water. The new reaction protocol can be applied to the nitroaldolreaction of nitroalkanes and α-ketoesters to construct the adjacent stereocenters of the chiral tertiary alcohol product with high diastereo- and enantioselectivity.