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
[EN] LABELED OXAZINOCARBAZOLES AS DIAGNOSTIC AGENTS<br/>[FR] OXAZINOCARBAZOLES MARQUES UTILES EN TANT QU'AGENTS DE DIAGNOSTIC
申请人:UPJOHN CO
公开号:WO2003089438A1
公开(公告)日:2003-10-30
The present invention provides isotopically labeled oxazinocarbazole derivatives having a ring connecting position 8 (C-8) and position 9 (N-9), and more specifically, provides compounds of formula (I) wherein R1, R2, R3 and R4 are described herein. These compounds are useful in the diagnostic analysis of diseases wherein modulation of 5-HT activity is desired.
Remarkable Ligand Effect on Rh-Catalyzed C–H-Active [3 + 2] Annulation of Ketimines and Alkynes
作者:Yan Shi、Yong Fang、Xu Zhao、Chengfeng Zhu、Xiang Wu、Xiaoming Yang、Yunfei Luo
DOI:10.1021/acs.orglett.0c01768
日期:2020.6.19
Externally added ligands were first found to have a significant impact on the Rh-catalyzed C–H-active [3 + 2] annulation of ketimines and alkynes. Olefin ligands have shown remarkable promotion effect for this reaction. The olefin promoted the reaction by increasing both the turnover rate and conversion of [Cp*RhCl2]2 in the formation of rhodacycle in the C–H activation step.
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
A new strategy for the enantioselective transfer hydrogenation of benzoxazines involving an in situ generation of Hantzsch ester has been developed. Dihydroadducts were isolated in good yields (75–99%) and enantioselectivities (89–96% ee).