Cu-catalyzed Recycling of Halogen Activating Groups via 1,3-Halogen Migration

A Cu(I)-catalyzed 1,3-halogen migration reaction effectively recycles an activating group by transferring bromine or iodine from a sp 2 to a benzylic carbon with concomitant borylation of the Ar-X bond. The resulting benzyl halide can be reacted in the same vessel under a variety of conditions to fo...

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Bibliographic Details
Published in:Journal of the American Chemical Society 2012-09, Vol.134 (39), p.16131-16134
Main Authors: Grigg, R. David, Van Hoveln, Ryan, Schomaker, Jennifer M.
Format: Article
Language:English
Online Access:Get full text
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Summary:A Cu(I)-catalyzed 1,3-halogen migration reaction effectively recycles an activating group by transferring bromine or iodine from a sp 2 to a benzylic carbon with concomitant borylation of the Ar-X bond. The resulting benzyl halide can be reacted in the same vessel under a variety of conditions to form an additional carbon-heteroatom bond. Cross-over experiments using an isotopically enriched bromide source support intramolecular transfer of Br. The reaction is postulated to proceed via a Markovnikov hydrocupration of the o -halostyrene, oxidative addition of the resulting Cu(I) complex into the Ar-X bond, reductive elimination of the new sp 3 C-X bond, and final borylation of an Ar-Cu(I) species to turn over the catalytic cycle.
ISSN:0002-7863
1520-5126
DOI:10.1021/ja306446m