AbstractWe report the Cu(II) catalyzed synthesis of β‐disubstituted ketones from styrene via oxo‐alkylation with unactivated cycloalkanes as the alkylating agent in presence of tert‐butylhydroperoxide (TBHP) and 1‐methylimidazole as oxidant and base respectively. β‐disubstituted ketones are known to be synthesized by using either expensive Ru/Ir complexes, or low‐cost metal complexes (e. g., Fe, Mn) with activated species like aldehyde, acid, alcohol, or phthalimide derivatives as the alkylating agent, however, use of unactivated cycloalkanes directly as the alkylating agent remains challenging. A wide range of aliphatic C−H substrates as well as various olefinic arenes and heteroarene (35 substrates including 14 new substrates) are well‐tolerated in this method. Hammett analysis shed more light on the substitution effect in the olefinic part on the overall mechanism. Furthermore, the controlled experiments, kinetic isotope effect study, and theoretical calculations (DFT) enable us to gain deeper insight of mechanistic intricacies of this new simple and atom‐economic methodology.
摘要 我们报告了在叔丁基过氧化氢(TBHP)和 1-甲基咪唑分别作为氧化剂和碱的存在下,以未活化的环烷烃为烷基化剂,通过氧化-烷基化反应催化苯乙烯合成 β-二取代酮的情况。众所周知,使用昂贵的 Ru/Ir 复合物或低成本的金属复合物(如铁、锰)与醛、酸、醇或邻苯二甲酰亚胺衍生物等活化物作为烷化剂,可以合成 β-二取代酮,但是直接使用未活化的环烷烃作为烷化剂仍然具有挑战性。在这种方法中,广泛的脂肪族 C-H 底物以及各种烯烃炔和杂芳烃(35 种底物,包括 14 种新底物)都能很好地耐受。Hammett 分析进一步揭示了烯烃部分的取代效应对整个机理的影响。此外,对照实验、动力学同位素效应研究和理论计算(DFT)使我们能够更深入地了解这种简单而原子经济的新方法的复杂机理。