Quite a pair: The first organocatalytic directasymmetric reduction of unprotected 1H‐indoles to chiral indolines has been developed. The reaction proceeds through the generation of electrophilic indolenium ions by a Brønsted acid, and then chiral Lewisbase (1) mediated enantioselective hydride transfer with HSiCl3. A variety of chiral indolines were obtained with moderate to excellent enantioselectivity
Asymmetric Transfer Hydrogenation of N-Unprotected Indoles with Ammonia Borane
作者:Weiwei Zhao、Zijia Zhang、Xiangqing Feng、Jing Yang、Haifeng Du
DOI:10.1021/acs.orglett.0c01930
日期:2020.8.7
A metal-free asymmetric transfer hydrogenation of unprotected indoles was successfully realized using a catalyst derived from HB(C6F5)2 and (S)-tert-butylsulfinamide with ammonia borane as a hydrogen source. A variety of indolines were achieved in 40–78% yields with up to 90% ee.
使用衍生自HB(C 6 F 5)2和(S)-叔丁基亚磺酰胺的氨硼烷作为氢源,成功实现了未保护的吲哚的无金属不对称转移氢化。各种二氢吲哚的收率为40-78%,ee高达90%。
Asymmetric hydrogenation of unprotected indoles using iridium complexes derived from P–OP ligands and (reusable) Brønsted acids
作者:José Luis Núñez-Rico、Héctor Fernández-Pérez、Anton Vidal-Ferran
DOI:10.1039/c3gc42132e
日期:——
stepwise process: (reusable) Brønsted acid-mediated CC isomerisation and asymmetrichydrogenationusing enantioselective iridium catalysts derived from P–OP ligands. This straightforward combination of (reusable) Brønstedacids, which activate the indole ring for hydrogenation by breaking its aromaticity, and enantiomerically pure [Ir(P–OP)]+ complexes as hydrogenation catalysts affords the resulting