Palone Andrea, Call Arnau, Garcia-Roca Aleria, Luis Josep M, Sigman Matthew S, Bietti Massimo, Nevado Cristina, Costas Miquel
Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, Girona, Catalonia, E-17071, Spain.
Department of Chemistry, University of Utah, Salt Lake City, Utah, 84112, USA.
Angew Chem Int Ed Engl. 2025 Jul 21;64(30):e202507755. doi: 10.1002/anie.202507755. Epub 2025 Jun 1.
Chiral polyoxygenated cyclohexanes are valuable constituents of biologically relevant products. Herein, we report a protocol for the direct access to these scaffolds via site- and enantioselective non-directed oxidation of cyclohexyl-3,5-meso diethers using aqueous H₂O₂. Structural shaping of a highly reactive chiral Mn-oxo species, achieved through the combination of a sterically encumbered ligand and a bulky carboxylic acid, promotes a precise fit of the substrate within the catalyst pocket, which translates into exceptional enantioselectivity (up to >99% ee). Computational studies reveal that C─H oxidation proceeds via an initial hydrogen atom transfer, followed by electron transfer, leading to the formation of a chiral cationic intermediate. The resulting desymmetrized 3-methoxycyclohexanone products serve as valuable intermediates for the synthesis of bioactive cores, as they can undergo orthogonal chemical modifications to enable further structural diversification.
手性多氧化环己烷是生物相关产品的重要组成部分。在此,我们报道了一种通过使用过氧化氢水溶液对环己基-3,5-内消旋二醚进行位点和对映选择性非导向氧化直接获得这些骨架的方法。通过空间位阻配体和大体积羧酸的组合实现的高活性手性锰氧物种的结构塑造,促进了底物在催化剂口袋内的精确契合,这转化为优异的对映选择性(高达>99% ee)。计算研究表明,C─H氧化通过初始氢原子转移进行,随后是电子转移,导致形成手性阳离子中间体。所得的去对称化3-甲氧基环己酮产物作为合成生物活性核心的有价值中间体,因为它们可以进行正交化学修饰以实现进一步的结构多样化。