Schiwek Christian H, Jandl Christian, Bach Thorsten
Department Chemie and Catalysis Research Center (CRC), Technische Universität München, 85747 Garching, Germany.
Org Lett. 2020 Dec 18;22(24):9468-9472. doi: 10.1021/acs.orglett.0c03427. Epub 2020 Nov 17.
The benzene ring of indolin-2-ones (2-oxindoles) and 3,4-dihydroquinol-2-ones was converted to a saturated cyclohexane ring by hydrogenation in the presence of the rhodium complex (CAAC)Rh(cod)Cl. The stereoselectivity of the process was found to be high with respect to both external substituent R within the saturated part of the heterocyclic ring and substituent X on the benzene ring. Twenty-one hexahydroindolin-2(3)-ones (70-99% yield, dr = 83/17 to >99/1) and twelve octahydro-2(1)-quinolinones (87-96% yield, dr = 64/36 to >99/1) were obtained with the major diastereoisomer exhibiting the hydrogen atoms in an all- arrangement. The high tolerance toward functional groups and the compatibility with existing stereogenic centers are key features of the hydrogenation protocol presented here.
在铑配合物(CAAC)Rh(cod)Cl存在下,通过氢化反应,吲哚啉-2-酮(2-氧化吲哚)和3,4-二氢喹啉-2-酮的苯环被转化为饱和环己烷环。结果发现,该反应对于杂环饱和部分内的外部取代基R以及苯环上的取代基X均具有较高的立体选择性。得到了21种六氢吲哚啉-2(3)-酮(产率70-99%,非对映体比例dr = 83/17至>99/1)和12种八氢-2(1)-喹啉酮(产率87-96%,非对映体比例dr = 64/36至>99/1),主要非对映异构体中的氢原子呈全顺式排列。对官能团的高耐受性以及与现有立体中心的兼容性是本文提出的氢化方法的关键特征。