N-H ketoimines 3a-3v are readily prepared in high yield via organometallic addition to nitrites and isolated as corresponding bench-stable hydrochloride salts. Homogeneous asymmetric hydrogenation of unprotected N-H ketoimines 3a-3v using Ir-(S,S)-f binaphane as catalyst provides chiral amines 4a-4v in 90-95% yield with enantioselectivities up to 95% ee.
Orthoacylimines: A New Class of Chiral Auxiliaries for Nucleophilic Addition of Organolithium Reagents to Imines
作者:Alessandro A. Boezio、Geoffrey Solberghe、Caroline Lauzon、André B. Charette
DOI:10.1021/jo026571m
日期:2003.4.1
orthoacylimine-derived chiral auxiliaries has been synthesized and tested in the nucleophilicaddition of organolithium reagents to imines. The precursors can be prepared by an aza-Wittig reaction between the corresponding orthoacyl azide and a variety of aldehydes in the presence of trialkylphosphines. The nucleophilicaddition of organolithium reagents led to the addition products in good yields
Rhodium-Catalyzed Asymmetric Hydrogenation of Unprotected NH Imines Assisted by a Thiourea
作者:Qingyang Zhao、Jialin Wen、Renchang Tan、Kexuan Huang、Pedro Metola、Rui Wang、Eric V. Anslyn、Xumu Zhang
DOI:10.1002/anie.201404570
日期:2014.8.4
Asymmetrichydrogenation of unprotected NH imines catalyzed by rhodium/bis(phosphine)‐thiourea provided chiral amines with up to 97 % yield and 95 % ee. 1H NMR studies, coupled with control experiments, implied that catalytic chloride‐bound intermediates were involved in the mechanism through a dual hydrogen‐bonding interaction. Deuteration experiments proved that the hydrogenation proceeded through
由铑/双(膦)-硫脲催化的未保护的NH亚胺的不对称氢化提供了手性胺,产率高达97%,ee值高达95% 。1 H NMR 研究与对照实验相结合,表明催化氯化物结合中间体通过双氢键相互作用参与了该机制。氘化实验证明氢化反应是通过与亚胺一致的途径进行的。
Chiral quaternary benzophenone hydrazonium salt derivatives; Efficient chiral catalysts for the enantioselective phase-transfer alkylation of imines. Application to synthesis of chiral primary amines
作者:J.Jamal Eddine、M. Cherqaoui
DOI:10.1016/0957-4166(95)00149-j
日期:1995.6
(2S)-1-Methyl-1-[N-(diphenylmethylene)]-2-hydroxymethylpyrrolidine hydrazonium iodide I-a has been designed to catalyse the enantioselective phase-transfer alkylation of N-(diphenylmethylene) benzenemethanamine II. Although the weak acidic character of the latter, alkylations have been performed within reasonable reaction times. Optically active Primary amines III a-e have been prepared in good chemical yields and up to 94% e.e. using 2-5 mol-% of the chiral catalyst only.
Commercial Transaminases for the Asymmetric Synthesis of Bulky Amines
作者:Marianne B. Haarr、Kotchakorn T. Sriwong、Elaine O'Reilly
DOI:10.1002/ejoc.202400257
日期:2024.6.17
Commercially available transaminases are valuable tools for the synthesis of chiral amine building blocks and are very accessible to the synthetic chemistry community. We demonstrate that selected commercially available enzymes from Codexis’ transaminase collection can accept and aminate bulky-bulky ketones in up to 99 % ee.