Substitution of a haloquinone by phenols under pyridine-free conditions: Synthetic, mechanistic, and solid-state considerations involving 2,3-dichloro- 1,4-naphthoquinone

Benzoquinones fused to heterocycles, like most benzoquinones, have the potential for a wide-array of applications but their inherent reactivity can present a synthetic dilemma. The issue is that a synthesis may target one desired outcome, yet yield a range of side products. In efforts to understand the reaction pathways of haloquinone substitution, while minimizing undesired product formation, four examples of reactions between 2,3-dichloro-1,4-naphthoquinone and phenolic nucleophiles are presented. Two of the products were confirmed and analyzed by X-ray crystallography. The reaction with orcinol was optimized for yield and investigation of this mechanism indicates a novel pathway under pyridine-free conditions.