Highly Effective Asymmetric Hydrogenation of Cyclic <i>N</i>-Alkyl Imines with Chiral Cationic Ru-MsDPEN Catalysts
作者:Fei Chen、Ziyuan Ding、Jie Qin、Tianli Wang、Yanmei He、Qing-Hua Fan
DOI:10.1021/ol201679f
日期:2011.8.19
A range of cyclic N-alkyl imines were efficiently hydrogenated by using a chiralcationic Ru(η6-cymene)(MsDPEN)(BArF) complex (MsDPEN = N-(methanesulfonyl)-1,2-diphenylethylenediamine) in high yields and up to 98% ee. A one-pot synthesis of chiral 2-phenylpyrrolidine via reductive amination was also developed.
Development of Chiral Bis-hydrazone Ligands for the Enantioselective Cross-Coupling Reactions of Aryldimethylsilanolates
作者:Scott E. Denmark、Wen-Tau T. Chang、K. N. Houk、Peng Liu
DOI:10.1021/jo502388r
日期:2015.1.2
aryldimethylsilanolates and arylbromides result in biaryl products with the same configuration and similar enantioselectivities implying that reductive elimination is the stereodetermining step. The origin of stereoselectivity is rationalized through computational modeling of diarylpalldium(II) complex which occurs through a conrotatory motion for the two aryl groups undergoing C–C bondformation.
organic azide to form an intermediate iminophosphorane and transfers the nitrene unit to the ruthenium providing an imido ruthenium intermediate which engages in the highly stereocontrolled C–H amination. This dual catalysis combines rutheniumcatalysis with the Staudinger reaction and provides a novel strategy for catalyzing enantioselective C–H aminations of unactivated aliphatic azides.