Chiral [RuCl2(dipyridylphosphane)(1,2-diamine)] Catalysts: Applications in Asymmetric Hydrogenation of a Wide Range of Simple Ketones
作者:Jing Wu、Jian-Xin Ji、Rongwei Guo、Chi-Hung Yeung、Albert S. C. Chan
DOI:10.1002/chem.200204688
日期:2003.7.7
The dipyridylphosphane/diamine-Ru complex combined with tBuOK in 2-propanol acts as a very effective catalyst system for the enantioselective hydrogenation of a diverse range of simple ketones including heteroaromatic ketones, substituted benzophenones, alkenyl ketones, and cyclopropyl ketones. The combination of desirable features, such as quantitative chemical yields within hours, broad substrate
Enzymatic resolution of (RS)-β-hydroxy selenides in organic media
作者:Carlos E. Costa、Giuliano C. Clososki、Henrique B. Barchesi、Sandra P. Zanotto、M. Graça Nascimento、João V. Comasseto
DOI:10.1016/j.tetasy.2004.11.007
日期:2004.12
Kinetic resolutions of a number of beta-hydroxy selenides promoted by enzymes were performed using PPL (free Porcine pancreatic lipase), PSL (Amano PS-free Pseudomonas sp. lipase) and CALB (NOVOZYM 435(R)-immobilized Candida Antarctica lipase type B) with (RS)-1-phenylselanyl-propan-2-ol. CALB gave the best results and provided both (R)- and (S)-enantiomers in high enantiomeric purity. A comparative study of the effect of temperature, solvent, enzyme immobilization and the structure of the substrates on the resolution is presented. (C) 2004 Elsevier Ltd. All rights reserved.
Kinetic resolution of fluoroalkyl (E)-vinyl carbinol derivatives by asymmetric epoxidation with titanium-tartrate catalysts.
Racemic fluoroalkyl (E) -vinyl carbinols (1a-d) were kinetically resolved by Sharpless epoxidation. The optical purity of the resolved alcohols was excellent (98% ee) in mono-and difluoromethyl derivatives (1b and 1c) and moderate (60% ee) in a trifluoromethyl compound (1a).
Highly Stereoselective C–C Bond Formation by Rhodium-Catalyzed Tandem Ylide Formation/[2,3]-Sigmatropic Rearrangement between Donor/Acceptor Carbenoids and Chiral Allylic Alcohols
作者:Zhanjie Li、Brendan T. Parr、Huw M. L. Davies
DOI:10.1021/ja303023n
日期:2012.7.4
The tandem ylide formation/[2,3]-sigmatropic rearrangement between donor/acceptor rhodium carbenoids and chiral allyl alcohols is a convergent C-Cbond forming process, which generates two vicinal stereogenic centers. Any of the four possible stereoisomers can be selectively synthesized by appropriate combination of the chiral catalyst Rh(2)(DOSP)(4) and the chiral alcohol.