Manganese-Pincer-Catalyzed Nitrile Hydration, α-Deuteration, and α-Deuterated Amide Formation via Metal Ligand Cooperation

A simple and efficient system for the hydration and alpha-deuteration of nitriles to form amides, alpha-deuterated nitriles, and alpha-deuterated amides catalyzed by a single pincer complex of the earth-abundant manganese capable of metal-ligand cooperation is reported. The reaction is selective and tolerates a wide range of functional groups, giving the corresponding amides in moderate to good yields. Changing the solvent from tert-butanol to toluene and using D2O results in formation of alpha-deuterated nitriles in high selectivity. Moreover, alpha-deuterated amides can be obtained in one step directly from nitriles and D2O in THF. Preliminary mechanistic studies suggest the transformations contributing toward activation of the nitriles via a metal-ligand cooperative pathway, generating the manganese ketimido and enamido pincer complexes as the key intermediates for further transformations.

Automated summary

A simple and efficient system utilizing a pincer complex of manganese has been developed for the hydration and alpha-deuteration of nitriles, providing amides, alpha-deuterated nitriles, and alpha-deuterated amides with good selectivity and moderate to good yields. The transformation proceeds through activation of nitriles via metal-ligand cooperation, generating key intermediates for further reactions.