Reductive Bromodifluoromethylation of Nitrones Promoted by Visible Light
作者:Igor A. Dmitriev、Vyacheslav I. Supranovich、Vitalij V. Levin、Alexander D. Dilman
DOI:10.1002/ejoc.201900274
日期:2019.7.14
A method for the synthesis of bromodifluoromethyl‐substituted hydroxylamines by reductive fluoroalkylation of nitrones with CF2Br2 is described. The reaction is promoted by visible light and employs ascorbic acid as a stoichiometric reducing agent.
Lewis base-catalyzed diastereoselective [3 + 2] cycloaddition reaction of nitrones with electron-deficient alkenes: an access to isoxazolidine derivatives
A Lewis base-catalyzed [3 + 2] cycloadditionreaction of nitrones with electron-deficientalkenes has been achieved under mild reaction conditions, affording various functionalized isoxazolidine derivatives as single diastereomers in moderate to excellent yields.
A radical type (3+3) cycloaddition of cyclopropane is realized with aryl cyclopropane and nitrone under photoredox catalysis in a highly regio- and diastereoselective manner. The reaction includes a stereospecific three-electron-type nucleophilic ring opening and a 6-endo-trig radical cyclization.
A variety of 4-phosphinylpyrrolidin-3-ones was prepared via a [3+2] cycloaddition between aryl aldonitrones and phosphinylallenes. The products were isolated as unique 4,5-trans diastereomers, in yields between 47% and 80%, over 23 examples. In the case of chiral racemic allenes, a 2:1 to 4:1 moderate 2,5-diastereoselectivity was observed. Under the reaction conditions, the cycloadducts directly undergo