Highly Enantioselective Pd-Catalyzed Asymmetric Hydrogenation of Activated Imines
作者:You-Qing Wang、Sheng-Mei Lu、Yong-Gui Zhou
DOI:10.1021/jo0700878
日期:2007.5.1
complexes are highly effective catalysts for asymmetrichydrogenation of activated imines in trifluoroethanol. The asymmetrichydrogenation of N-diphenylphosphinyl ketimines 3 with Pd(CF3CO2)/(S)-SegPhos indicated 87−99% ee, and N-tosylimines 5 could gave 88−97% ee with Pd(CF3CO2)/(S)-SynPhos as a catalyst. CyclicN-sulfonylimines 7 and 11 were hydrogenated to afford the useful chiral sultam derivatives in
Pd /双膦配合物是用于活化的亚胺在三氟乙醇中不对称氢化的高效催化剂。Pd(CF 3 CO 2)/(S)-SegPhos对N-二苯基亚膦酰基酮亚胺3的不对称氢化表明ee为87-99%,N- tosylimines 5与Pd(CF 3 CO 2)可以得到88-97%ee /(S)-SynPhos作为催化剂。环状N-磺酰亚胺7和11 进行氢化,以79-93%ee的比重得到有用的手性舒马坦衍生物,这是重要的有机合成中间体和农业和医药制剂的结构单元。
Asymmetric Synthesis of α-Allyl-α-Aryl α-Amino Acids by Tandem Alkylation/π-Allylation of α-Iminoesters
作者:John M. Curto、Joshua S. Dickstein、Simon Berritt、Marisa C. Kozlowski
DOI:10.1021/ol500506t
日期:2014.4.4
The first asymmetric synthesis of α-allyl-α-aryl α-amino acids by means of a three-componentcoupling of α-iminoesters, Grignard reagents, and cinnamyl acetate is reported. Notably, the enolate from the tandem process provides a much higher level of reactivity and selectivity than the same enolate generated via direct deprotonation, presumably due to differences in the solvation/aggregation state.
Highly Enantioselective Transfer Hydrogenation of α-Imino Esters by a Phosphoric Acid
作者:Qiang Kang、Zhuo-An Zhao、Shu-Li You
DOI:10.1002/adsc.200700235
日期:2007.7.2
Chiral phosphoric acids have been identified as highly efficient organocatalysts for the asymmetric transferhydrogenation of α-imino esters and amide. Utilizing Hantzsch esters as the hydrogen donor, versatile highly enantioenriched α-amino esters and their derivatives were obtained with up to 98 % ee.
Enantioselective hydrosilylation of N-aryl and N-benzyl ketimines with trichlorosilane catalyzed by readily accessible chiral N-picolinoylaminoalcohols proceeded smoothly furnishing chiral secondary amines in good yields (up to 93%) and moderate to excellent enantioselectivities (up to 95% ee). (c) 2007 Published by Elsevier Ltd.
Diastereoselective Reduction of α-Imino Esters with Tris(trimethylsilyl)aluminum
Tris(trimethylsilyl)aluminum was found to be a good chemoselective reducing reagent for alpha-imino esters to give alpha-amino esters in good yields. Application to the reduction of 3,5-disubstituted 5,6-dihyro-2H-1,4-oxazine2-ones realized a stereoselective conversion into cis-3,5-disubstituted morpholine-2-ones.