A practical, electrochemical method is developed for the direct dehydrogenative lactonization of C(sp2/sp3)–H bonds under external oxidant- and metal-free conditions, delivering diverse lactones, including coumarin derivatives with excellent regioselectivity. The scalable nature of this newly developed electrochemical process was demonstrated on a 40 g scale following an operationally simple protocol
A variety of functionalized coumarins were synthesized from substituted phenylacrylic acids via PIDA/I2-mediated and irradiation-promoted oxidative carbon–oxygen bond formation. Our studies show that the oxygen in the pendant carboxylic acid group cyclizes favorably to the aryl ring that is cis to it. The main advantages of this method include good functional group tolerance and the transition-metal-free
通过PIDA / I 2介导的和辐射促进的氧化碳-氧键形成,由取代的苯基丙烯酸合成了多种功能化的香豆素。我们的研究表明,羧酸侧基中的氧有利地环化成顺式的芳基环。该方法的主要优点包括良好的官能团耐受性和无过渡金属的特性。