ACS Catalysis p. 9015 - 9024 (2019)
Update date:2022-07-29
Topics: Catalyzed Mechanism Scope Ester Cleavage Reductions La[N(SiMe3)2]3 Ester reduction Pinacolborane
Barger, Christopher J.
Motta, Alessandro
Weidner, Victoria L.
Lohr, Tracy L.
Marks, Tobin J.
Tris[N,N-bis(trimethylsilyl)amido]lanthanum (LaNTMS) is an efficient, highly active, and selective homogeneous catalyst for ester reduction with pinacolborane (HBpin). Alkyl and aryl esters are cleaved to the corresponding alkoxy- and aryloxy-boronic esters which can then be straightforwardly hydrolyzed to alcohols. Ester reduction is achieved with 1 mol % catalyst loading at 25-60 °C, and most substrates are quantitatively reduced in 1 h. Nitro, halide, and amino functional groups are well tolerated, and ester reduction is completely chemoselective over potentially competing intra- or intermolecular alkene or alkyne hydroboration. Kinetic studies, isotopic labeling, and density functional theory calculations with energetic span analysis argue that ester reduction proceeds through a rate-determining hydride-transfer step that is ligand-centered (hydride is transferred directly from bound HBpin to bound ester) and not through a metal hydride-based intermediate that is often observed in organolanthanide catalysis. The active catalyst is proposed to be a La-hemiacetal, [(Me3Si)2N]2La-OCHR(OR)[HBpin], generated in situ from LaNTMS via hydroboronolysis of a single La-N(SiMe3)2 bond. These results add to the growing compendium of selective oxygenate transformations that LaNTMS is competent to catalyze, further underscoring the value and versatility of homoleptic lanthanide complexes in homogeneous catalytic organic synthesis.
View MoreShandong Xiangde Biotechnology Co., Ltd
Contact:+86 -15066639877
Address:Sanba street
Wuxi Innopal International Trade CO.,LTD
Contact:+86-510-80711901-8003
Address:Room 402,Building 5,Longze Garden,No.17,South huanjiu Road,Yixing City, Jiangsu,China
Qingdao Pana-Life Biochem Co.,Ltd.
Contact:86-532-87683902
Address:No.967 Dalao Road, Licang Zone, Qingdao City,Shandong, China 266021
suzhou chukai pharmateach co,.ltd
Contact:86-512-88812511
Address:Building 3, Wujiang Scientific Innovation Park, 2358 Changan Rd, Wujiang 215200, Jiangsu Province, P. R. China
Chuzhou Baiao Biologhy S&T Co., Ltd.
Contact:+86-25-83212599;+86-25-83212699 13705185959
Address:Room 905, Tianzheng International Platza, No.399, Zhongyang Road ,Nanjing, Jiangsu Province, China
Doi:10.1039/c6ra24291j
(2016)Doi:10.1002/ejic.201301499
(2014)Doi:10.1016/j.jorganchem.2014.01.027
(2014)Doi:10.1002/pro.2948
(2016)Doi:10.1016/j.tetlet.2014.01.123
(2014)Doi:10.1021/om00020a034
(1994)