Catalytic, Asymmetric Michael-Aldol Annulations via a Stereodivergent/Stereoconvergent Path Operating under Curtin–Hammett Control
作者:Mitchell T. Giordano、Katelyn M. Kitzinger、Pedro de Jesús Cruz、Shubin Liu、Jeffrey S. Johnson
DOI:10.1021/jacs.3c03373
日期:2023.6.7
contiguous stereocenters (diastereoselection up to >20:1, enantioselectivity up to >99:1) in a Michael/aldol domino reaction between trisubstituted electrophilic alkenes and γ-nitroketones. Mechanistic studies suggest a scenario in which stereoconvergency is achieved by kinetically controlledcyclization after the initial diastereodivergent Michael addition. Diastereoconvergency during cyclization is shown
Selectivity of Daucus carota roots and baker’s yeast in the enantioselective reduction of γ-nitroketones
作者:Dina Scarpi、Ernesto G. Occhiato、Antonio Guarna
DOI:10.1016/j.tetasy.2005.03.002
日期:2005.4
The enantioselective reduction of a series of aromatic gamma-nitroketones was achieved by using Daticus carota roots in water, which afforded the corresponding (S)-alcohols with ees ranging from 73% to 100%. A comparison of these results with the data obtained by reducing the same substrates with baker's yeast resulted in D. carota always being more enantioselective than baker's yeast, although a lower number of substrates were reduced. The possible influence of the aromatic ring substituents on the reaction outcome is also discussed. (c) 2005 Elsevier Ltd. All rights reserved.