科研之友
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摘要
The first direct C-H b-trifluoromethylation of unsubstituted or a-alkyl-substituted alpha,beta-unsaturated carbonyl compounds under metal-free conditions was realized with excellent regio- and stereoselectivity as well as a very broad substrate scope. Both olefinic and allylic trifluoromethylation products are accessible with high selectivities by altering the substrate substitutions. The resultant olefinic products, namely (E)-beta-trifluoromethyl (CF3) alpha,beta-unsaturated hydroxamic acid derivatives, served as acceptors in organocatalytic asymmetric Michael addition reactions to give hydroxamic acid derivatives bearing a chiral CF3-substituted stereocenter with high enantioselectivities.
