Enantioselective Base-Free Phase-Transfer Reaction in Water-Rich Solvent
作者:Rongjun He、Seiji Shirakawa、Keiji Maruoka
DOI:10.1021/ja906821y
日期:2009.11.25
development of enantioselective phase-transfercatalysis for preparing important natural products or physiologically active compounds is quite attractive and challenging in terms of environmental consciousness. Although quaternary ammonium salts as phase-transfer catalysts are believed to require base additives for phase-transferreactions, we have discovered that even without any base additives, the enantioselective
Nickel(II)-Catalyzed Asymmetric Michael Addition of Oxindoles with Modified N,N,O-Tridentate Chiral Phenanthroline Ligands
作者:Yuki Naganawa、Hisao Nishiyama、Hiroki Abe
DOI:10.1055/s-0035-1561630
日期:——
Nickel(II)-catalyzed enantioselective Michael addition of N-Boc-oxindole derivatives with methyl vinyl ketone was demonstrated to give the corresponding adducts having chiral all-carbon quaternary centers with up to 87% ee in the presence of axially chiral N,N,O-tridentate phenanthroline ligand.
在轴向手性 N,N 存在下,镍 (II) 催化的 N-Boc-羟吲哚衍生物与甲基乙烯基酮的对映选择性迈克尔加成得到相应的加合物,其具有高达 87% 的 ee 手性全碳季中心, O-三齿菲咯啉配体。
Efficient approach for the design of effective chiral quaternary phosphonium salts in asymmetric conjugate additions
approach for the design of chiral quaternary phosphonium bromides as chiral phase-transfer catalysts was demonstrated. A catalyst library of phosphonium salts with various structures was readily constructed using commercially available chiral phosphines as catalyst precursors, and an optimized catalyst was successfully applied to highlyenantioselectiveconjugateadditions under base-free phase-transfer