In tandem: A divergent and enantioselectiveapproach to 2,3‐disubstitutedindolines was developed throughconsecutiveBrønstedacid/Pd‐complex‐promotedtandemreactions from simple 2‐substituted indoles and aldehydes in one operation to give up to 98 % ee (see scheme; R1=H, F, or Me; R2=alkyl; R3=aryl or alkyl). Three Brønstedacidpromoted steps and two Pd‐catalyzed hydrogenation steps were involved
串联:通过一次简单的2-取代的吲哚和醛类的连续Brønsted酸/ Pd-络合物促进的串联反应,开发了一种对2,3-二取代的二氢吲哚的发散和对映选择性的方法,使ee高达98% (参见方案) ; R 1= H,F或Me; R 2=烷基; R 3=芳基或烷基)。此过程涉及三个Brønsted酸促进步骤和两个Pd催化的氢化步骤。
Direct Asymmetric Hydrosilylation of Indoles: Combined Lewis Base and Brønsted Acid Activation
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%。
Enantioselective hydrogenation of N-heteroaromatics catalyzed by chiral diphosphine modified binaphthyl palladium nanoparticles
application of binaphthyl-stabilized palladium nanoparticles (Bin-PdNPs) with chiral modifiers in asymmetric hydrogenation of N-heteroaromatics is revealed. With an appropriate ratio of R-BINAP/Bin-PdNPs used, the pre-prepared chiral nanocatalyst achieves asymmetric hydrogenations of 2-substituted quinolines with good to excellent yields and moderate enantioselectivities, which showed superior catalytic properties
Chiral 2,3-Disubstituted Indolines from Indoles and Aldehydes by Organocatalyzed Tandem Synthesis Involving Reduction by Trichlorosilane
作者:Lin Chen、Chao Wang、Li Zhou、Jian Sun
DOI:10.1002/adsc.201301133
日期:2014.7.7
The organocatalytic trichlorosilanereduction system has been successfully utilized to develop a multi‐step tandem approach for the easy preparation of chiral 2‐methyl‐3‐alkylindolines starting from simple 2‐methylindoles and aldehydes. A broad range of chiral 2‐methyl‐3‐alkylindoline products was obtained with high yields and enantioselectivities and excellent stereoselectivities by this approach