The first transition metal–ligand complex-catalyzed regioselective and stereoselective aminohalogenation of cinnamic esters
作者:Han-Xun Wei、Sun Hee Kim、Guigen Li
DOI:10.1016/s0040-4020(01)00228-9
日期:2001.4
Transition metal-ligand complex-catalyzed regio- and stereoselective aminohalogenation of cinnamic esters has been developed using p-TsNCl2 as the nitrogen and chlorine sources. Dichloro-(1,10-phenanthroline)-palladium (II) as the catalyst can be handled very conveniently due to its property of less hygroscopic as compared with other aminohalogenation catalysts. The reaction is suggested to proceed through the mechanism involving N-tosyl N-chloro aziridinium intermediate. Eight examples are presented with modest to good yields (56-82%) and excellent stereoselectivity (> 10:1). (C) 2001 Elsevier Science Ltd. All rights reserved.
Ionic liquid media resulted in more efficient regio- and stereoselective aminohalogenation of cinnamic esters
作者:S.R.S. Saibabu Kotti、Xin Xu、Yining Wang、Allan D. Headley、Guigen Li
DOI:10.1016/j.tetlet.2004.08.040
日期:2004.9
The ionic liquid, butylmethylimidazolium tetrafluoroborate ([Bmim][BF4]), was found to be superior to classical organic solvents for the metal catalyzed regio- and stereoselective aminohalogenation of cinnamic esters. The aminohalogenation reaction of cinnamic esters with p-TsNCl2 proceeded at a faster rate (within 12 h) in the presence of a reduced amount of catalyst (CuOTf, 6.0 mol%). Good yields (76-82%) and excellent regio- and stereoselectivity (one isomer) were achieved for eight examples. (C) 2004 Elsevier Ltd. All rights reserved.