Electrochemical Regioselective Sulfenylation of 2<i>H-</i>Indazoles with Thiols in Batch and Continuous Flow
Kuldeep Singh Bhati, Riya Nagar, Bhanwar Kumar Malviya, Monika Shukla, Amanpreet Kaur Jassal, Ved Prakash Verma, Dinesh Kumar Yadav, Neetu Kumari, Siddharth Sharma
Abstract
A novel electrochemical cross-dehydrogenative C–S bond coupling of aryl thiols with 2H-indazole is reported. Thiol-functionalized 2H-indazoles were synthesized under catalyst-, oxidant-, and metal-free conditions with innocuous hydrogen as the sole byproduct at ambient temperature. Furthermore, continuous electrochemical flow conditions using a graphite/Ni flow cell were used to obtained 3-(arylthio)-2H-indazole compounds on a gram scale within the residence time of 39 min. Detailed mechanistic studies including control experiments and cyclic voltammetry are provided to support the radical–radical cross-coupling pathway.