Copper-Catalyzed Borylative Cyclization of in Situ Generated o-Allenylaryl Nitriles with Bis(pinacolato)diboron.

A Cu-catalyzed cascade borylcupration/cyclization of in situ generated allene-nitriles with B2pin2 has been developed, which provides highly substituted 3-boryl-1-naphthylamines with excellent regioselectivity and wide functional group compatibility. It has been shown that, for the first time, the catalytically generated allylcopper species can be captured by a cyano group from a normal nitrile to furnish a carbocycle.