Isothiourea-catalysed transfer hydrogenation of α,β-unsaturated para-nitrophenyl esters
A protocol for the isothiourea-catalysed transfer hydrogenation of α,β-unsaturated para-nitrophenyl esters using Hantzsch ester has been developed. Good to excellent yields are observed using α,β-unsaturated aryl esters bearing electron-withdrawing β-subs
Smith, Andrew D.,Wu, Jiufeng,Young, Claire M.
supporting information
(2020/12/21)
Construction of CF3-containing quaternary chiral centers via Michael addition reactions
Michael addition reactions of a variety of Grignard reagents to 4,4,4-trifluorinated α,β-unsaturated carboxylic acid derivatives with 4-substituted oxazolidin-2-ones as a chiral auxiliary were found to occur smoothly in the presence of CuBr·SMe2 and TMSCl
Catalytic asymmetric hydrogenation of α-CF3- or β-CF3-Substituted acrylic acids using Rhodium(I) complexes with a combination of chiral and achiral ligands
Only the mixture works! Acrylic acid derivatives with CF3 substituents in α or β position were efficiently hydrogenated in the presence of a RhI complex with a chiral secondary phosphine oxide (SPO; see scheme) and an achiral Ph3P as ligands. The corresponding propanoic acid derivatives were obtained with generally high conversion (>99 %) and high enantioselectivity (92->99 %). Copyright
Dong, Kaiwu,Li, Yang,Wang, Zheng,Ding, Kuiling
supporting information
p. 14191 - 14195
(2014/01/06)
A rapid access to both enantiomers of 1,2,3,4-tetranor B-trienic 18,18,18-trifluorosteroids. The first enantiocontrolled total synthesis of 18,18,18-trifluorosteroids
Chiral A-tetranor B-trienic 18,18,18-trifluorosteroid 2a and its enantiomer 1a were synthesised by the thermolysis of chiral olefinic benzocyclobutenes 7b and 7a which were in turn prepared by the aldol reaction of chiral oxazolidinone 5 and 11 with 2-(4-