One-Pot Synthesis of α-Amino Bisphosphonates from Nitriles via Tf 2 O/HC(OR) 3 -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 in situ generated by treatment of nitrile with readily accessible Tf 2 O/HC(OR 1 ) 3 , 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 J P-C couplings including unusual five-bond long-range 5 J P-C and 3 J P-C across quaternary carbon and hetero (N) atoms were observed in 13 C NMR spectra.