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。
A New Phosphine-Amine-Oxazoline Ligand for Ru-Catalyzed Asymmetric Hydrogenation of<i>N</i>-Phosphinylimines
作者:Xiaochen Ma、Lin Qiao、Guixia Liu、Zheng Huang
DOI:10.1002/cjoc.201800343
日期:2018.12
A series of chiral phosphine‐amine‐oxazoline (PAO) ligands with an NH moiety were synthesized and applied to the ruthenium‐catalyzed asymmetric hydrogenation of N‐phosphinylimines. The ligand bearing phenyl groups at the phosphorus moiety and isopropyl at the oxazoline moiety exhibits good activity and excellent enantioselectivity (up to 99% ee). This catalytic system provides an efficient and mild
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).
Aromatic motifs in the design of Ephedra ligands for application in the asymmetric addition of diethylzinc to aldehydes and diphenylphosphinoylimines
作者:Sucharita Banerjee、Anthony J. Camodeca、Gregory G. Griffin、Christopher G. Hamaker、Shawn R. Hitchcock
DOI:10.1016/j.tetasy.2010.02.026
日期:2010.3
Using N-benzylephedrine as a model, a collection of N-arylmethylephedrine derivatives has been prepared. These derivatives were prepared by treatment of ephedrine with selected aldehydes to create oxazolidines 8a-e. Reduction of the oxazolidines with lithium aluminum hydride afforded the target beta-amino alcohols 9a-e. When applied in the catalytic asymmetric addition of diethylzinc to aldehydes and diphenylphosphinoylimines, the derivatives yielded product enantioselectivities that were comparable to those of N-benzylephedrine. An N-cyclohexylmethylephedrine derivative was also prepared: this 13-aminoalcohol did not perform well in the catalytic addition of diethylzinc to 2-naphthaldehyde, thus suggesting that the aromatic motif is important in terms of maintaining a reasonable level of asymmetric induction. Finally, N-benzyl-N-methyl-2-amino-1,2-diphenyl-1-ethanol, an analogue of the N-benzylephedrine derivative, was prepared. This compound yielded comparable enantioselectivities in the catalytic asymmetric addition when employed as a ligand. (C) 2010 Elsevier Ltd. All rights reserved.