Highly diastereo- and enantioselective copper-catalyzed methylboration of 1,2-dihydroquinolines and 2H-chromenes

A Cu-catalyzed asymmetric methylboration of 1,2-dihydroquinolines, 2H-chromenes and 2H-thiochromenes providing boryl products bearing two adjacent chiral centers with excellent selectivities, up to 99 : 1 dr and 99.9% ee, has been realized for the first time.