Morsy Rana M I, Samala Ganesh, Jalan Ankur, Kopach Michael E, Venneti Naresh M, Stockdill Jennifer L
Department of Chemistry, Wayne State University Detroit MI 48202 USA
Eli Lilly and Company Indianapolis IN 46285 USA.
Chem Sci. 2023 Jul 13;14(34):9016-9023. doi: 10.1039/d3sc00045a. eCollection 2023 Aug 30.
Phosphines and phosphites are critical tools for non-metal desulfurative methodologies due to the strength of the P[double bond, length as m-dash]S bond. An overarching premise in these methods has been that stoichiometric (or excess) P(iii) reagent is required for reactivity. Despite decades of research, a desulfurative process that is catalytic in phosphine/phosphite has not been reported. Here, we report the successful merging of two thermal radical processes: the desulfurization of unactivated and activated alkyl thiols and the reduction of P(v) = S to P(iii) by reaction with a silyl radical species. We employ catalytic trimethyl phosphite, catalytic azo-bis(cyclohexyl)nitrile, and two equivalents of tris(trimethylsilyl)silane as the stoichiometric reductant and sulfur atom scavenger. This method is tolerant of common organic functional groups and affords products in good to excellent yields.
由于P=S键的强度，膦和亚磷酸酯是非金属脱硫方法的关键工具。这些方法的一个总体前提是，反应需要化学计量（或过量）的P(iii)试剂。尽管经过了数十年的研究，但尚未报道过在膦/亚磷酸酯中具有催化作用的脱硫过程。在此，我们报告了两个热自由基过程的成功结合：未活化和活化的烷基硫醇的脱硫，以及通过与硅基自由基物种反应将P(v)=S还原为P(iii)。我们使用催化量的亚磷酸三甲酯、催化量的偶氮双（环己基）腈和两当量的三（三甲基硅基）硅烷作为化学计量的还原剂和硫原子清除剂。该方法对常见的有机官能团具有耐受性，并且能以良好到优异的产率提供产物。
