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。
Highly Enantioselective Pd-Catalyzed Asymmetric Hydrogenation of <i>N</i>-Diphenylphosphinyl Ketimines
作者:Yong-Gui Zhou、You-Qing Wang
DOI:10.1055/s-2006-939712
日期:——
A variety of substituted N-diphenylphosphinyl imines were hydrogenated using Pd(CF3CO2)2/(S)-SEGPHOS as a catalyst with high enantioselectivities (86.7%-98.6% ee).
Enantioselective Strecker-type reaction of phosphinoyl ketimines catalyzed by a chiral Zr-bipyridyldiol catalyst
作者:Yi-Jing Chen、Chinpiao Chen
DOI:10.1016/j.tetasy.2008.09.011
日期:2008.9
An enantioselective Strecker reaction of N-diphenylphosphinoyl ketimines with TMSCN employing a chiral zirconium complex formed from chiral bipyridyl diol 1 as catalyst is described. The catalytic efficiency of chiral ligand 1 with other Lewis acids was also explored. Higher yields (50-85%) with moderate to good enantioselectivities (30-80%) were achieved for a variety of N-diphenylphosphinoyl ketimines. (C) 2008 Elsevier Ltd. All rights reserved.
Catalytic Enantioselective Allylation of Ketoimines
A general catalytic allylation of simple ketoimines was developed using 1 mol % of CuF(.)3PPh(3) as catalyst, 1.5 mol % of La((OPr)-Pr-/)(3) as the cocatalyst, and stable and nontoxic allylboronic acid pinacol ester as the nucleophile. This reaction constituted a good template for developing the first catalytic enantioselective allylation of ketoimines. In this case, using (LiOPr)-Pr-i as the cocatalyst produced higher enantioselectivity and reactivity than La((OPr)-Pr-i)(3). Thus, using the CuF-cyclopentyl-DuPHOS complex ( 10 mol %) and (LiOPr)-Pr-i ( 30 mol %) in the presence of tBuOH (1 equiv) produced high enantioselectivity up to 93% ee from a range of aromatic ketoimines. Mechanistic studies indicated that (LiOPr)-Pr-i accelerates the reaction by increasing the concentration of an active nucleophile, allylcopper.
Enantioselective MSPV Reduction of Ketimines Using 2-Propanol and (BINOL)Al<sup>III</sup>
作者:Christopher R. Graves、Karl A. Scheidt、SonBinh T. Nguyen
DOI:10.1021/ol060110w
日期:2006.3.1
A highly enantioselective Meerwein-Schmidt-Ponndorf-Verley (MSPV) reduction of N-phosphinoyl ketimines by (BINOL)Al-III/2-propanol is reported. Yields ranging between 79 and 85% with high enantiomeric excesses (93-98%) are observed for a wide range of structurally diverse ketimines. A [2.0.4] bicyclic chelation model is proposed to account for this high selectivity.