Pd-Catalyzed C–O Bond Formation Enabling the Synthesis of Congested N,N,O-Trisubstituted Hydroxylamines

A Pd-catalyzed C–O cross-coupling of O-acyl hydroxylamines and tertiary or secondary alkyl electrophiles was reported without the cleavage of the rather fragile N–O bond. The described strategy provides direct access to congested N,N,O-trisubstituted hydroxylamines bearing an α-quaternary carbon center under mild conditions in high yields and features exclusively chemoselective C–O bond formation, a broad substrate scope, and excellent functional group tolerance. The synthetic potential of the cross-coupling was established via pharmaceuticals derivatizations and a series of postcatalytic modifications.