In(OTf)(3)-catalyzed N-alpha phosphonylation of N,O-acetals with triethyl phosphite

A practical approach to alpha-aminophosphonates has been developed through an In(OTf)(3)-catalyzed N-alpha phosphonylation of N,O-acetals with triethyl phosphite 7. Indoline and isoindoline N,O-acetals 6a-6j and 9a-9j and chain N,O-acetals 11a-11p were subjected to a Lewis acid catalyzed N-alpha phosphonylation process. As a result, the desired alpha-aminophosphonates 8a-8j, 10a-10j and 12a-12p were obtained in moderate to good yields.