Department of Chemistry, University of Nebraska-Lincoln , Lincoln, Nebraska 68588-0304, United States.
J Am Chem Soc. 2017 Apr 26;139(16):5740-5743. doi: 10.1021/jacs.7b02581. Epub 2017 Apr 17.
Oxime-directed catalytic asymmetric hydroboration is diverted to catalytic asymmetric hydrogenation (CAH) upon the addition of a proton source, such as MeOH, or by running the reaction under a hydrogen atmosphere. A borane (e.g., pinacolborane) is required to promote CAH. Tri- and tetrasubstituted alkenes, including the challenging all-alkyl tetrasubstituted alkenes, undergo CAH with enantiomer ratios (er) as high as 99:1. The mild reaction conditions, i.e., ambient temperature, moderate reaction times, and the need for only a slight excess of H, contrast those used in most state-of-the-art catalysts for related substrates.
当添加质子源（如甲醇）或在氢气气氛下进行反应时，肟定向催化不对称硼氢化反应会转向催化不对称氢化（CAH）。需要硼烷（例如频哪醇硼烷）来促进 CAH。三取代和四取代烯烃，包括具有挑战性的全烷基四取代烯烃，都可以进行 CAH，对映体比例（er）高达 99:1。温和的反应条件，即环境温度、适中的反应时间以及仅需要稍微过量的 H，与大多数最先进的相关底物催化剂的反应条件形成对比。
