Apical Functionalization of Chiral Heterohelicenes

We describe a synthetic protocol to selectively functionalize chiral bridged triarylamines at the apical position using regioselective copper-catalyzed amination reaction. This protocol allows the coupling of diphenylamines with a sterically hindered but electronically activated aryl–Br bond in the presence of a sterically unhindered but electronically unactivated aryl–Br bond. The unactivated aryl–Br bond was utilized further to synthesize a chiral heterohelicene homodimer using Stille coupling