Electrochemical pinacol coupling of carbonyl compounds in an undivided cell with a sacrificial anode would be a promising approach toward synthetically valuable vic-1,2-diol scaffolds without using low-valent metal reductants. However, sacrificial anodes produce an equimolar amount of metal waste, which may be a major issue in terms of sustainable chemistry. Herein, we report a sacrificial anode-free electrochemical protocol for the synthesis of pinacol-type vic-1,2-diols from sec-alcohols, namely benzyl alcohol derivatives and ethyl lactate. The corresponding vic-1,2-diols are obtained in moderate to good yields, and good to high levels of stereoselectivity are observed for sec-benzyl alcohol derivatives. The present transformations smoothly proceed in a simple undivided cell under constant current conditions without the use of external chemical oxidants/reductants, and transition-metal catalysts.
在带有牺牲阳极的不分化电池中进行羰基化合物的电化学嚬哪醇偶联,是在不使用低价金属还原剂的情况下合成有价值的沧-1,2-二醇支架的一种可行方法。然而,牺牲阳极会产生等摩尔量的金属废物,这可能是可持续化学方面的一个主要问题。在此,我们报告了一种以仲醇(即苄醇衍生物和乳酸乙酯)为原料合成频哪醇型沧海1,2-二醇的无牺牲阳极电化学方案。相应的沧海-1,2-二醇的收率从中等到良好,仲苄基醇衍生物的立体选择性从良好到较高。在恒流条件下,无需使用外部化学氧化剂/还原剂和过渡金属催化剂,即可在一个简单的未分割电池中顺利进行上述转化。