Alternating Current Promoted Radical-radical Cross-coupling For N-S Bond And C-S Bond Formation

Organosulfur compounds are very important substances in the field of organic synthesis and biological research.Among the sulfur-containing organic compounds,organic compounds containing N-S and C-S bonds are widely used in biopharmaceutical and industrial fields.Traditional methods of constructing N-S and C-S bonds often rely on pre-functionalization,metal catalysis,and the addition of stoichiometric redox agents.Although these methods are mature,they inevitably cause some problems such as chemical pollution and low atomic economy.In recent years,organic electrochemical synthesis has achieve rapid development,which realizes the redox reaction through the electron gain and loss of the reactant on the electrode surface,so there is no need to add an redox agent.The electrochemical reaction controls the reaction by controlling the current and voltage,so it has great application prospects in industrial production.Common electrochemical reactions are usually divided into anodic oxidation type electrolysis,cathode reduction type electrolysis and paired electrolysis.Among them,paired electrolysis uses intermediates produced by anodic oxidation and cathode reduction to construct new chemical bonds.There are relatively few reports on paired electrolysis,because the reaction intermediates need to undergo a mass transfer process,which is not conducive to the transfer of highly active intermediates.AC electrolysis can not only control the reaction through current and voltage,but also control the reaction through frequency.At the same time,the oxidation reaction and the reduction reaction can occur in an electrode.In this paper,thiols or thiophenols,and,electron-poor aniline derivatives are used as substrates to realize the direct coupling of NH/SH and CH/SH direct coupling using AC electrolysis.Not only clarified the construction method of N-S bond and C-S bond in detail,but also systematically studied the influence of frequency on electrochemical reaction in the process of AC electrolysis.The following results have been obtained in related research:1.Successfully realized the nitrogen-sulfur coupling of electron-poor amine and thiol or thiophenol under the conditions of AC electrolysis,and synthesized a series of sulfenamide derivatives with different structures.The electrochemical method not only has good general applicability,but also the general yield can reach a medium to excellent level,with the highest yield reaching 93%;at the same time,the reaction also has a good reaction effect when it is scaled up to 10 mmol;2.Successfully realized the CH/SH coupling of electron-poor amines and thiols or thiophenols under AC electrolysis;3.Successfully proved the influence of AC frequency on the reaction effect,which opened up a new way for the synthesis of sulfenamide the way.