Eureka! We found it! Acetonitrile is not easily activated or even deprotonated. A combination of the strong Lewis acid (C2
triethylamine, however, is able to deprotonate CH3
CN. The resulting cyanomethyl function is bound to the phosphorus moiety, affording the highly stable salt
CN)]. Using more nucleophilic secondary and primary amines instead of NEt3
leads to a phosphate featuring an amidine ligand, which formally results from hydroamination of acetonitrile by the amine. More information can be found in the
by B. Hoge et al.