Photocatalytic Three-Component Reductive Coupling Synthesis of <i>gem</i>-Difluorohomoallyl Secondary Amines
Bingbing Feng, Meifang Tang, Rui Xiao, Qing Wang, Gangguo Zhu, Zuxiao Zhang, Zheliang Yuan, Yanan Wang
Abstract
gem -Difluorohomoallyl amines, an important class of gem -difluoroalkenes, are prevalent moieties in many bioactive compounds. However, limited methods are suitable for the synthesis of this type of compound containing secondary amines. Here, we display a photocatalytic multicomponent protocol for the synthesis of gem -difluoroalkenes containing secondary amines, which makes use of readily available materials: arylamines, alkyl aldehydes, and α-trifluoromethyl alkenes. Moreover, ketones and secondary amines are also suitable substrates. Preliminary mechanistic experiments indicate that a key α-amino radical was involved, generated from the reduction of in situ-formed imines (or iminium ions) by a reduced photocatalyst. Subsequent addition of the α-amino radical to α-trifluoromethyl alkenes and β-F elimination deliver the desired products.