Rhenium-Catalyzed Regio- and Stereoselective Addition of Imines to Terminal Alkynes Leading to N-Alkylideneallylamines
摘要:
The reaction of terminal allcynes with imines using ReBr(CO)(5) as a catalyst results in the production of N-alkylideneallylamines and not the conventional propargylamines. The substituent on the imine nitrogen is important, and a diphenylmethyl group gave the best result. The catalytic cycle of this regio selective C-C bond forming reaction appears to involve the formation of an alkynyl rhenium species and subsequent nucleophilic attack of the alkynyl beta-carbon atom on the imine carbon to give a vinylidene rhenium species.
Synthesis of <i>N</i>-alkylated lipopeptides and their application as organocatalysts in asymmetric Michael addition in aqueous environments
作者:José A. C. Delgado、Fidel E. M. Vicente、Alexander F. de la Torre、Vitor A. Fernandes、Arlene G. Corrêa、Márcio W. Paixão
DOI:10.1039/d1nj01112j
日期:——
through an isocyanide-based multicomponent reaction. Various structural motifs were tunably introduced on the catalyst backbone with the aim of incorporating amphiphilic features. Consequently, they have further been evaluated in the 1,4-addition of aldehydes to trans-β-nitrostyrene having water as the sole solvent. Under sustainable reactionconditions, Michael adducts were obtained in excellent yields