The direct Michaeladdition of aldehydes and ketones to nitroolefins, catalyzed by N-i-Pr-2,2′-bipyrrolidine, is described. The desired 1,4-adducts are obtained in excellent yields with enantioselectivities up to 95% ee and dr up to 95 : 5 of the syn aldehydeaddition product. An unexpected inversion of diastereoselectivity was observed for the addition of α-hydroxy ketones to β-arylnitroolefins with
Organocatalytic Enantioselective Synthesis of Highly Functionalized Polysubstituted Pyrrolidines
作者:Nerea Ruiz、Efraím Reyes、Jose L. Vicario、Dolores Badía、Luisa Carrillo、Uxue Uria
DOI:10.1002/chem.200800788
日期:2008.10.20
adducts. 3,4-Disubstituted pyrrolidines have been obtained in a single step by Zn-mediated chemoselective reduction of the nitro group followed by intramolecular reductive amination, and trisubstituted homoproline derivatives have been prepared by means of an olefination reaction and a cascade process involving chemoselective reduction of the nitro group followed by a fully diastereoselective intramolecular