Enantioselective synthesis of amino acids from ammonia

Metal-catalysed reactions involving ammonia gas are plagued by ammonia’s strong Lewis basicity, which leads to poor chemoselectivity and enantioselectivity. Here we introduce a strategy for preparing chiral α-amino acids directly from ammonia. By the cooperative action of copper complexes and chiral hydrogen-bond donors, enantioselective insertion of carbenes into the N–H bond of ammonia can construct C–N bonds in excellent yield and enantioselectivity. Using this method, we coupled a wide variety of diazoesters with ammonia to produce natural and non-natural chiral α-amino acids, which have a wide range of applications in pharmaceutical and biochemistry research. Our work provides a general method for asymmetric transformations involving ammonia.