Electrophilic amination of carbanions by N-carboxamido oxaziridines
作者:Alan Armstrong、Mark A Atkin、Steven Swallow
DOI:10.1016/s0040-4039(00)00140-4
日期:2000.3
3-aryl-N-carboxamido oxaziridines have been prepared and tested as reagents for electrophilicamination of carbanions. The 3-(2-cyanophenyl)-derivative gave highest yields of amination product, and was used for amination of ketone, ester and amide enolates, as well as sulfone-, phosphonate- and nitrile-stabilized carbanions.
The development of new approaches to obtain optically pure β-hydroxy esters is an important area in synthetic organic chemistry since they are precursors of other high value compounds. Herein, the kineticresolution of racemic β-hydroxy esters using a planar-chiralDMAPderivative catalyst is presented. Following this procedure, a range of aromatic β-hydroxy esters was obtained in excellent selectivities
作者:Laura Sgreccia、Marco Bandini、Stefano Morganti、Arianna Quintavalla、Achille Umani-Ronchi、Pier Giorgio Cozzi
DOI:10.1016/j.jorganchem.2007.02.037
日期:2007.7
A catalytic titaniummediated Reformatsky reaction is presented. The technique employs cyclopentadienyltitaniumdichloride(IV) (10 mol%) in conjunction with Mn (2 equiv.), as the stoichiometric reductant, and (CF3CO)2O (1.5 equiv.), as the scavenger, and it is based on the formation of titanocene(III) chloride as a mild and homogeneous single-electron reductant. The reaction gives moderate yields of
Asymmetric dehydration of β-hydroxy esters via kinetic resolution
作者:Yongtae Kim、Eui Ta Choi、Min Hee Lee、Yong Sun Park
DOI:10.1016/j.tetlet.2007.02.111
日期:2007.4
Catalytic asymmetricdehydration of β-hydroxyesters via kineticresolution has been investigated. The kineticresolution of rac-β-hydroxy esters in the presence of prolinol chiral ligand 2a and BrZnCH2CO2t-Bu can provide highly enantioenriched β-hydroxyesters 3 and 5–11 with selectivity factors ranging from 15 to 42.
已经研究了通过动力学拆分对β-羟基酯进行催化不对称脱水的方法。的动力学拆分外消旋-β-羟基酯在存在脯氨醇手性配体2A和BrZnCH 2 CO 2吨-Bu能够提供对映体富集的高度β羟基酯3和5 - 11有选择性因素,从15至42。
(R)-(+)-N-Methylbenzoguanidine ((R)-NMBG) catalyzed acylative kinetic resolution of racemic 3-hydroxy-3-aryl-propanoates
作者:Akira Yamada、Kenya Nakata
DOI:10.1016/j.tetlet.2016.09.014
日期:2016.10
cyclohexane carboxylic anhydride under mild reaction conditions. A tert-butyl ester moiety is necessary to achieve a high selectivity. The effects of the substituents on the aromatic rings of the substrates were systematically investigated, and diverse substrates participated in the reaction with good s-values (>20) irrespective of the type of substituents and their patterns, except for o-methoxy group