Iridium-Catalyzed Asymmetric Ring-Opening of Oxabenzonorbornadienes with N-Substituted Piperazine Nucleophiles
作者:Wen Yang、Renshi Luo、Dingqiao Yang
DOI:10.3390/molecules201219748
日期:——
Iridium-catalyzed asymmetric ring-opening of oxabenzonorbornadienes with N-substituted piperazines was described. The reaction afforded the corresponding ring-opening products in high yields and moderate enantioselectivities in the presence of 2.5 mol % [Ir(COD)Cl]2 and 5.0 mol % (S)-p-Tol-BINAP. The effects of various chiral bidentate ligands, catalyst loading, solvent, and temperature on the yield and enantioselectivity were also investigated. A plausible mechanism was proposed to account for the formation of the corresponding trans-ring opened products based on the X-ray structure of product 2i.
Asymmetric ring-opening of oxabenzonorbornadiene with amines promoted by a chiral iridium-monophosphine catalyst
作者:Renshi Luo、Jianhua Liao、Ling Xie、Wenjun Tang、Albert S. C. Chan
DOI:10.1039/c3cc46009f
日期:——
A new iridium-monophosphine catalyst is found to be efficient for asymmetric ring-opening of benzonorbornadiene with amines, providing a series of chiral substituted dihydronaphthalenes in high yields (up to 98%) and excellent enantioselectivities (>99%).
Highly Efficient Rhodium-Catalyzed Asymmetric Ring-Opening Reactions of Oxabenzonorbornadiene with Amine Nucleophiles
作者:Yuhua Long、Shuangqi Zhao、Heping Zeng、Dingqiao Yang
DOI:10.1007/s10562-010-0383-3
日期:2010.8
yields (up to 97%) with excellent enantioselectivities (up to 99%ee).Graphical AbstractRhodium-catalyzed asymmetricring-openingreactions of oxabenzonorbornadienes with aliphatic primary amines and substituted N-phenylpiperazines were investigated. These reactions are featured with the formation of a new carbon-nitrogen bond via an intermolecular allylic displacement of the bridgehead oxygen with amine
A new tunable chiral monophosphine was used as a ligand for asymmetric rhodium-catalyzed ring-opening of oxabenzonorbornadiene with amines, providing a series of chiral ring-opened products in high yields (up to 97%) and with high enantioselectivities (>99%).The reaction can be performed at rt to obtain the desired product with high enantioselectivity. (C) 2014 Elsevier Ltd. All rights reserved.