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Published on: October 5, 2019
Chemoselective transfer hydrogenation of alkynoates enabled by Cu(I)-photosensitizer catalysis
Kun Zhang1, Ziwen Huang1, Yin Xu1
1State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, College of Chemical Engineering, Zhejiang University of Technology, Hangzhou, 310014, P. R. China. yinxu1994@zjut.edu.cn.
Abstract:
Hydrogenation reactions are of great value in synthetic chemistry; however, it has been challenging to distinguish the reactivity of various reactive motifs. Herein, we report a novel strategy for the transfer hydrogenation of alkynes to alkanes enabled by Cu(I) photosensitizer catalysis. This photoredox protocol creatively employs a Hantzsch ester/tertiary amine as the reductant and hydrogen source. More importantly, it enables the highly chemoselective functionalization of alkynoates in the presence of other reactive motifs, such as benzyl esters, pyridines, and even electron-neutral alkynes, thus establishing a complementary approach to all the previous alkyne hydrogenation methodologies.
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