Asymmetric synthesis of β-aryl-β-trifluoromethyl-β-aminoarones via Mannich-type reactions of ketone enolates with chiral aryl CF3-substituted N-tert-butanesulfinyl ketimines
作者:Yingle Liu、Yangen Huang、Feng-Ling Qing
DOI:10.1016/j.tet.2012.04.070
日期:2012.6
A method for the preparation of chiral beta-aryl-beta-trifluoromethyl-beta-aminoarones has been developed involving the Mannich-type reactions of ketone-derivative enolates with chiral aryl CF3-substituted N-tert-butanesulfinyl ketimines. This method tolerates a wide of aromatic ketones, giving the products in moderate to excellent yields (up to 91%) with good diastereoselectiveties (up to 93:7 dr). Acidic cleavage of the tert-butanesulfinyl group gave optically pure beta-aryl-beta-trifluoromethyl-beta-aminoarones in excellent yields (up to 98%), which can be further transformed into CF3-substituted aziridine derivatives. (C) 2012 Elsevier Ltd. All rights reserved.
Highly diastereoselective synthesis of α-trifluoromethylated α-propargylamines by acetylide addition to chiral CF3-substituted N-tert-butanesulfinyl ketimines
作者:Hengqiao Xiao、Yangen Huang、Feng-Ling Qing
DOI:10.1016/j.tetasy.2010.11.028
日期:2010.12
A convenient and practical method for the preparation of enantiomerically pure alpha-trifluoromethylated alpha-propargylamines is described. A range of enantiopure alpha-trifluoromethylated alpha-propargyl sulfinamides were obtained by the addition of lithium acetylides generated in situ with n-BuLi and terminal alkynes to diverse chiral CF3-substituted (S)-N-tert-butanesulfinyl ketimines in moderate to excellent yields (56-97%) and with uniformly excellent diastereoselectivities (>99:1) by using Ti((OPr)-Pr-i)(4) as the catalyst and THF as the polar solvent. Enantiomerically pure alpha-trifluoromethylated alpha,alpha-dibranched propargyl amines were then readily obtained in excellent yields (87-97%) by acidic cleavage of the tert-butanesulfinyl group. (C) 2010 Elsevier Ltd. All rights reserved.