One-Pot Synthesis of α-Amino Bisphosphonates from Nitriles via TfO/HC(OR)-Mediated Interrupted Ritter-Type Reaction.

A versatile synthesis of α-amino bisphosphonates has been achieved through one-pot interrupted Ritter-type reaction under mild conditions. The reactive Ritter intermediate nitrilium is generated by treatment of nitrile with readily accessible TfO/HC(OR), which is trapped by phosphite ester to deliver the desired product. This protocol is efficient, scalable, and well compatible with a broad scope of substrates. In addition, plentiful characteristic couplings including unusual five-bond long-range and across quaternary carbon and hetero (N) atoms were observed in C NMR spectra.