Chemoselective Cyclodehydration of α‐Acyl‐β‐arylaminoacrylamides Using Hendrickson Reagent: Access to Polysubstituted 4‐Aminoquinolines and Diazaphenacenes

Abstract

A chemoselecive cyclodehydration of α-acyl-β-arylaminoacrylamides via an electrophilic activation strategy has been described. A series of substituted 4-aminopyridines are chemoselectively prepared in 73-92% yields from α-acyl-β-arylaminoacrylamides activated by hexaphenyloxodiphosphonium triflate (Hendrickson reagent), whereas substituted diaza[n]phenacenes (n = 4-6) are obtained in 72-93% yields directly from α-acyl-β-arylaminoacrylamides using Hendrickson reagent in combination with triflic anhydride (Tf 2 O). The synthetic protocols feature with readily available starting materials, mild reaction conditions, simple execution, and wide range of synthetic potential of products.