Bradsher Cycloaddition

Abstract

This reaction was first reported by Bradsher in 1958 and was extensively explored by Bradsher and co‐workers in the following two decades. It is the [4 + 2] cycloaddition of a common dienophile with cationic aromatic azadienes, such as acridizinium and isoquinolinium, to form a tricyclic system containing as many as four chiral centers and an iminium ion. Therefore, this reaction is generally known as the Bradsher cycloaddition.