Oxidative Photocatalytic Homo- and Cross-Coupling of Phenols: Nonenzymatic, Catalytic Method for Coupling Tyrosine

An oxidative photocatalytic method for phenol–phenol homo- and cross-coupling is described, and isolated yields of 16–97% are obtained. Measured oxidation potentials and computed nucleophilicity parameters support a mechanism of nucleophilic attack of one partner onto the oxidized neutral radical form of the other partner. Our understanding of this model permitted the development of cross-coupling reactions between nucleophilic phenols/arenes and easily oxidized phenols with high selectivity and efficiency. A highlight of this method is that one equivalent of each coupling partner is utilized. Building on these findings, a nonenzymatic, catalytic method for coupling tyrosine was also developed.

本研究报道了一种用于酚（phenol）类自身偶联与交叉偶联的氧化光催化方法，所得分离产率可达16%~97%。通过实测氧化电位与计算得到的亲核性参数，证实了该反应的机理为：一个偶联底物亲核进攻另一底物被氧化生成的中性自由基中间体。基于该反应模型的机理认知，我们成功开发出亲核性酚类/芳烃与易氧化酚类之间的高选择性、高效率交叉偶联反应。该方法的一大亮点在于，两种偶联底物各需使用1当量。基于上述研究发现，本团队还开发了一种非酶催化的酪氨酸（tyrosine）偶联方法。