Synthesis of Quaternary -Amino Esters: A Remarkably Broad Substrate Scope in Aza-Friedel−Crafts Alkylation

A versatile synthetic protocol of aza-Friedel−Crafts alkylation has been developed for the synthesis of quaternary a-amino esters. This operationally simple alkylation proceeds under ambient conditions with high efficiency, regioselectivity, and an exceptionally broad scope of arene nucleophiles. A key feature of this alkylation is the role associated with the silver(I) salt counteranions liberated during the reaction. Taking advantage of a phase-transfer counteranion/BrØnsted acid pair mechanism, a catalytic enantioselective version of the reaction is also reported.