Asymmetric Pnictogen-Bonding Catalysis: Transfer Hydrogenation by a Chiral Antimony(V) Cation/Anion Pair
作者:Jian Zhang、Jun Wei、Wei-Yi Ding、Shaoyu Li、Shao-Hua Xiang、Bin Tan
DOI:10.1021/jacs.1c02808
日期:2021.5.5
Pnictogen-bonding catalysisbased on σ-hole interactions has recently attracted the attention of synthetic chemists. As a proof-of-concept for asymmetric pnictogen-bonding catalysis, we report herein an enantioselective transfer hydrogenation of benzoxazines catalyzed by a novel chiral antimony cation/anion pair. The chiral pnictogen catalyst library could be rapidly accessed from triarylstibine with
A metal-free hydrogenation of 3-substituted 2H-1,4-benzoxazines
作者:Simin Wei、Xiangqing Feng、Haifeng Du
DOI:10.1039/c6ob01556e
日期:——
A metal-free hydrogenation of 3-substituted 2H-1,4-benzoxazines has been successfully realized with 2.5 mol% of B(C6F5)3 as a catalyst to furnish a variety of 3,4-dihydro-2H-1,4-benzoxazines in 93–99% yields. Up to 42% ee was also achieved for the asymmetric hydrogenation with the use of a chiral diene and HB(C6F5)2.
以2.5摩尔%的B(C 6 F 5)3为催化剂,成功地实现了3取代2 H -1,4-苯并恶嗪的无金属氢化,以提供各种3,4-二氢-2 H -1,4-苯并恶嗪的产率为93-99%。通过使用手性二烯和HB(C 6 F 5)2进行不对称氢化反应,还可以达到高达42%ee 。
A series of tunable and regenerable biomimetic hydrogen sources, 4,5-dihydropyrrolo[1,2-a]quinoxalines, have been synthesized and applied in biomimetic asymmetric hydrogenation of 3-aryl-2H-benzo[b][1,4]oxazines and 1-alkyl-3-aryl-quinoxalin-2(1H)-ones, providing the chiral amines with up to 92% and 89% ee, respectively.
合成了一系列可调和可再生的仿生氢源4,5-二氢吡咯并[1,2- a ]喹喔啉,并将其用于3-芳基-2 H-苯并[ b ] [1,4]的仿生不对称加氢。恶嗪和1-烷基-3-芳基-喹喔啉-2(1 H)-酮,分别为手性胺提供高达92%和89%的ee。
A Rhodium-Catalyzed [3 + 2] Annulation of General Aromatic Aldimines/Ketimines and <i>N-</i>Substituted Maleimides
作者:Chengfeng Zhu、Jichao Luan、Jun Fang、Xu Zhao、Xiang Wu、Yougui Li、Yunfei Luo
DOI:10.1021/acs.orglett.8b02671
日期:2018.9.21
A new class of rhodium-catalyzed, C–Hactivation triggered [3 + 2] annulations of aromatic aldimines or ketimines and maleimides was reported in this study. A broad scope of general imines without electron-withdrawing groups were successfully activated and could effectively react with N-substituted maleimide to afford pericyclic, multichiral centered amines in good yields and with excellent diastereoselectivity