Palladium-catalyzed 1,1-alkynylbromination of alkenes with alkynyl bromides |
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| Authors: | Yusuke Ano Natsuki Kawai Naoto Chatani |
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| Institution: | Department of Applied Chemistry, Faculty of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 Japan.; Center for Atomic and Molecular Technologies, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 Japan |
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| 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.The first Pd-catalyzed 1,1-alkynylbromination of terminal alkenes using alkynyl bromides, which provides direct access to a variety of functionalized propargylic bromides without the need for an external brominating reagent, is reported. |
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