A Cu(I) catalyst effectively transfers a bromine or iodine from an sp2 carbon to the benzylic position of an ortho-halide styrene with concomitant borylation of the Ar-X bond.  This reaction represents a coupling between an aryl halide and a borane with concomitant recycling of the activating halide group.  The benzyl halide can further be reacted in the same pot to form a new carbon-heteroatom bond and the boronic ester can be used to form a new carbon-carbon bond.  When chiral phosphine ligands are employed for this reaction, enantioenriched benzyl halides are produced.  The mechanism is believed to proceed via Markonikov hydrocupration of the olefin followed by 1,3-migration to generate an Ar-Cu species which then undergoes subsequent borylation to turn over the catalytic cycle.

Copper-mediated 1,3-halogen migration

245th National Meeting (2013)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.