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
applied to a highly efficient Pd-catalyzed enantioselectivehydrogenation of substituted indoles. The methodology was suitable for the hydrogenation of indoles substituted at the 2-, 3- and 2,3-positions. Products were obtained in quantitative conversion and up to 98% ee. The role the 2-position substituent plays in the hydrogenation process has been proposed. The methodology could be used as an alternative
A palladium-catalyzed asymmetric hydrogenation of unprotected 3-substituted indoles was developed, providing a series of 3-substituted indolines in excellent yields with ≤94.4:5.6 er. The large sterically hindered bisphosphine ligand played a crucial role in the enantioselective control. In addition, the gram-scale hydrogenation experiment and product derivatizations were performed successfully.
开发了一种钯催化的未保护的 3-取代吲哚的不对称氢化,以 ≤94.4:5.6 er 的优异收率提供了一系列 3-取代二氢吲哚。大的空间位阻双膦配体在对映选择性控制中起着至关重要的作用。此外,成功地进行了克级加氢实验和产品衍生化。