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
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.
Two homochiral organocatalytic metal organic materials with nanoscopic channels
作者:Zhuxiu Zhang、Young Ran Ji、Lukasz Wojtas、Wen-Yang Gao、Shengqian Ma、Michael J. Zaworotko、Jon C. Antilla
DOI:10.1039/c3cc43801e
日期:——
Two homochiral organocatalytic MOMs were prepared using tetra- and octa-carboxylate ligands, respectively. The nanoscopic channels in these MOMs are lined by organonocatalytic chiral phosphoric acid derivatives of binol and ocMOM-1 exhibited improved enantioselectivity over the parent ligand in the context of transfer hydrogenation of a series of benzoxazines.
Rh(III)-catalyzed 1:2 coupling of 3-aryl-2H-benzo[b][1,4]oxazines with α-diazo-β-ketoesters has been realized for mild synthesis of spiropyrans. The reaction proceeded via twofold C-H activation followed by unusual [3+3] and [4+2] annulation with decent functional group tolerance. Moreover, A pyranoid-skelecton intermediate has been isolated as a key intermediate as a result of mono-alkylation and