Catalyst- and additive-free [3 + 3] cyclization–aromatization of β,γ-dioxobutanoate with amines for synthesis of p-aminophenols

A [3 + 3] cyclization–aromatization of β,γ-dioxobutanoate with amines for synthesis of p -aminophenols under catalyst- and additive-free conditions was developed. The reaction displays high efficiency in the late-stage modification of drug molecules.