在催化量的对映体纯的溴化铵,金鸡纳生物碱和K 2 CO 3的存在下,将(三氟甲基)三甲基硅烷化学选择性加成到芳基乙二醛的α-亚氨基酮上,生成O-甲硅烷基化的β-亚氨基醇。随后用NaBH 4还原这些产物,得到β-(N-烷基)氨基-α-三氟甲基醇,在最佳条件下,其ee值为30 – 71%。根据在手性溶剂化剂存在下记录的1 H或19 F NMR光谱确定最终产物的对映体过量。
The reactions of α-imino ketones, derivedfrom arylglyoxals, with (trifluoromethyl)trimethylsilane (CF3SiMe3) in DME solution, in the presence of catalytic amount of CsF, at room temperature, yield O-silylated β-imino alcohols in the chemoselective manner. Subsequent reduction of these products with NaBH4 in ethanolic solution leads to the corresponding β-(N-alkyl)amino-α-trifluoromethyl alcohols in
The asymmetric transfer hydrogenation of representative aryl and benzofuranyl 2-tert-butylaminoethanones with formic acid-triethylamine, catalyzed by RhCl[(R,R)-T5DPEN](C5Me5), produced the corresponding beta-tert-butylamino alcohols in 97-99% ee. A short asymmetric synthesis of (R)-bufuralol, a potent beta-adrenergic receptor antagonist, is described. This approach to beta-amino alcohols from ketones circumvents the halogenation-reduction-amination sequence. (C) 2010 Elsevier Ltd. All rights reserved.
Chemoselective trifluoromethylation of the C N group of α-iminoketones derived from arylglyoxals
作者:Emilia Obijalska、Marcin K. Kowalski、Grzegorz Mlostoń、Anthony Linden、Heinz Heimgartner
DOI:10.1016/j.jfluchem.2014.09.002
日期:2014.12
Chemoselective addition of (trifluoromethyl)trimethylsilane to the C=N group of N-(tert-butyl)-alpha-iminoketones in the presence of a fluoride ion as a catalyst was achieved under acidic conditions. Subsequent diastereoselective reductions of the obtained alpha-amino-alpha-(trifluoromethyl)ketones led to beta-amino-beta-(trifluoromethyl) alcohols in very good yields and high diastereoselectivities. Different reducing agents were tested; the reduction performed with LiAlH4 and Raney-Ni, respectively, afforded the desired diastereoisomers in a reversed ratio. (C) 2014 Elsevier B.V. All rights reserved.
Nucleophilic addition of (difluoromethyl)trimethylsilane to selected α-imino ketones and aryl diketones
作者:Emilia Obijalska、Greta Utecht、Marcin K. Kowalski、Grzegorz Mlostoń、Michał Rachwalski
DOI:10.1016/j.tetlet.2015.06.025
日期:2015.8
addition of (difluoromethyl)trimethylsilane (CHF2SiMe3) to the carbonyl bond of aryl glyoxal derived α-imino ketones, and selected diaryl 1,2-diketones were studied in the presence of initiators, such as potassium tert-butoxide or caesium fluoride. Subsequent reduction of the obtained α-imino alcohols and α-hydroxy ketones with sodium borohydride gave the expected 2-amino 1-(difluoromethyl)alcohols and
Enantioselective additions of (trifluoromethyl)trimethylsilane to α-imino ketones derived from aryl glyoxals
作者:Emilia Obijalska、Grzegorz Mlostoń、Alice Six
DOI:10.1016/j.tetlet.2013.02.093
日期:2013.5
Chemoselective additions of (trifluoromethyl)trimethylsilane to α-imino ketones derivedfrom aryl glyoxals in the presence of a catalytic amount of enantiomerically pure ammonium bromides, derivedfrom Cinchona alkaloids and K2CO3 led to O-silylated β-imino alcohols. Subsequent reduction of these products with NaBH4 gave β-(N-alkyl)amino-α-trifluoromethyl alcohols for which the ee values were 30–71%
在催化量的对映体纯的溴化铵,金鸡纳生物碱和K 2 CO 3的存在下,将(三氟甲基)三甲基硅烷化学选择性加成到芳基乙二醛的α-亚氨基酮上,生成O-甲硅烷基化的β-亚氨基醇。随后用NaBH 4还原这些产物,得到β-(N-烷基)氨基-α-三氟甲基醇,在最佳条件下,其ee值为30 – 71%。根据在手性溶剂化剂存在下记录的1 H或19 F NMR光谱确定最终产物的对映体过量。