“…In this respect, the combination of an appropriate catalyst and nonmetallic reducing reagents such as hydrazine hydrate (N 2 H 4 ·H 2 O) and boranes (NH 3 ·BH 3 , B 2 pin 2 , and HBpin) was widely explored (Scheme B). More recently, the transition-metal-catalyzed hydrogenation of azobenzenes under Pd/C, Mn(I), and Ru(II) was reported by the Balaraman, Rueping, and Xu groups . However, the chemoselectivity for such a process should be difficult to control if other reducible groups are contained …”