Institut de Química Computacional I Catàlisi (IQCC), Departament de Química, Universitat de Girona, Campus Montilivi, 17071, Girona, Catalonia, Spain.
Organic Chemistry & Catalysis, Debye Institute for Nanomaterials Science, Utrecht University, Universiteitsweg 99, 3584, CG Utrecht, The Netherlands.
Angew Chem Int Ed Engl. 2016 May 4;55(19):5776-9. doi: 10.1002/anie.201600785. Epub 2016 Apr 5.
Bulky iron complexes are described that catalyze the site-selective oxidation of alkyl C-H bonds with hydrogen peroxide under mild conditions. Steric bulk at the iron center is introduced by appending trialkylsilyl groups at the meta-position of the pyridines in tetradentate aminopyridine ligands, and this effect translates into high product yields, an enhanced preferential oxidation of secondary over tertiary C-H bonds, and the ability to perform site-selective oxidation of methylenic sites in terpenoid and steroidal substrates. Unprecedented site selective oxidation at C6 and C12 methylenic sites in steroidal substrates is shown to be governed by the chirality of the catalysts.
描述了庞大的铁配合物，它们在温和条件下用过氧化氢催化烷基 C-H 键的选择性氧化。在四齿氨吡啶配体中，通过在吡啶的间位附加三烷基硅基，在铁中心引入空间位阻，这一效应转化为高产物收率、增强的仲 C-H 键相对于叔 C-H 键的优先氧化以及对萜类和甾体底物中亚甲基位点进行选择性氧化的能力。显示甾体底物中亚甲基位点 C6 和 C12 的前所未有的选择性氧化受催化剂手性的控制。
