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Palladium-catalyzed 1,1-alkynylbromination of alkenes with alkynyl bromides
Yusuke Ano1,2, Natsuki Kawai1, Naoto Chatani1
1Department of Applied Chemistry, Faculty of Engineering, Osaka University 2-1 Yamadaoka, Suita Osaka 565-0871 Japan ano@chem.eng.osaka-u.ac.jp.
Abstract:
The palladium-catalyzed 1,1-alkynylbromination of terminal alkenes with a silyl-protected alkynyl bromide is reported. The method tolerates a diverse range of alkenes including vinylarenes, acrylates, and even electronically unbiased alkene derivatives to afford propargylic bromides regioselectively. Mechanistic studies and DFT calculations indicate that the 1,1-alkynylbromination reaction proceeds via the migration of the Pd center followed by the formation of a π-allenyl Pd intermediate, leading to the stereoselective reductive elimination of the C(sp3)-Br bond at the propargylic positon.
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