近日，香港城市大学谭雪锋团队研究了铁介导的硼二碘甲烷与烯烃的电化学环丙烷化。2026年2月26日，《中国化学》杂志发表了这一成果。

环丙烷是一种独特的环状结构单元，被广泛引入药物分子中以增强其效力。开发高效构建环丙烷（尤其是带有官能团的环丙烷）的合成方法，既具有实际意义，也具有学术价值。在已报道的方法中，偕二卤化物经还原后与烯烃发生环化反应，是最有效、最直接的[2+1]合成策略之一。然而，大多数相关方法依赖于光化学途径，这严重限制了其实际应用。此外，近年来卤化物的电化学催化还原反应备受关注，主要使用镍和钴催化剂。

研究组报道了一种铁介导的电化学还原二碘甲基硼酸酯的方法，随后与烯烃发生环丙烷化反应，从而快速构建环丙基硼酸酯。该方法对多种带有不同官能团的底物均表现出良好的耐受性，凸显了其在后期修饰中的便捷性。在不延长反应时间且保持相同电流密度的条件下进行的克级规模合成，得到了相似的结果，进一步证明了该方法的实际应用价值。环丙烷上的硼酸酯基团易于转化，为其在药物化学中的进一步应用铺平了道路。值得注意的是，包括对照实验和循环伏安法研究在内的机理研究表明，铁物种——无论是铁盐还是铁/2,2'-联喹啉络合物——都能有效促进电化学环丙烷化反应。鉴于铁是一种廉价的材料，其作为牺牲阳极和促进剂的双重作用增强了该方法的实用性。

附：英文原文

Title: Iron-Mediated Electrochemical Cyclopropanation of Borodiiodomethane with Alkenes†

Author: Jie Li, Yingying Pan, Xin Wang, Xuefeng Tan

Issue&Volume: 2026-02-26

Abstract: Cyclopropane is a unique ring motif widely incorporated into pharmaceuticals to enhance their potency. Developing synthetic methods for the efficient construction of cyclopropanes, particularly those with functional groups, is of both practical significance and academic interest. Among the reported methods, the reduction of gem-dihalides followed by cyclization with alkenes represents one of the most efficient and straightforward [2+1] approaches. However, most references rely on photochemical pathways, which severely limit practical applications. Additionally, electrochemical catalytic reduction of halides has gained significant attention in recent years, primarily using nickel and cobalt catalysts. In this study, we introduce an iron-mediated electrochemical reduction of borodiiodomethane, followed by cyclopropanation with alkenes, enabling rapid fabrication of cyclopropylboronates. Substrates with a wide range of functional groups are well tolerated, demonstrating the ease of late-stage modifications. Gram-scale synthesis, conducted without extending reaction time and maintaining the same current density, yielded similar results, highlighting the method's practical application. The boronate group on the cyclopropane can be easily transformed, paving the way for further applications in medicinal chemistry. Notably, mechanistic investigations, including control experiments and cyclic voltammetry studies, revealed that iron species—both the Fe salt and the Fe/2,2'-biquinoline complex—can effectively promote electrochemical cyclopropanation. Given that iron is an inexpensive material, its dual role as both sacrificial anode and promoter enhances the practicality of this method.

DOI: 10.1002/cjoc.70509

Source: https://onlinelibrary.wiley.com/doi/10.1002/cjoc.70509