Preparation and Lipase-catalyzed Optical Resolution of 2,2,2-Trifluoro-1-(naphthyl) ethanols
作者:Katsuya Kato、Masato Katayama、Rakesh K. Gautam、Shozo Fujii、Hiroshi Kimoto
DOI:10.1271/bbb.59.271
日期:1995.1
The optical resolution of racemic 2,2,2-trifluoro-1-(naphthyl)ethanols (TFNEs) was achieved by lipase-catalyzed enantioselective acetylation with vinyl acetate in octane, S-acetates and R-alcohols being obtained. The introduction of a methyl group into the naphthalene ring at the 4-position (2b) or the 2-position (2c) markedly decreased the reactivity, in particular for 2c. 2,2,2-Trifluoro-1-(1-naphthyl)ethanol (2a) behaved differently from the regio-isomer, 2,2,2-trifluoro-1-(2-naphthyl)ethanol (2d): The enantioselectivity of lipases [LIP (Pseudomonas), PLC (Alcaligenes), and ALC (Achromobacter)] was high for 2a but low for 2d, whereas lipases [AK and PS (Pseudomonas)] exhibited higher selectivity for 2d than for 2a. Three other derivatives, 2,2,2-trifluoro-1-(phenyl)ethanol (2e), 2,2,2-trifluoro-1-(indol-3-yl)ethanol (2f), and 1-(1-naphthyl)ethanol (2g), were prepared, and their behaviors with respect to lipase-catalyzed acetylation were compared with 2a.
对消旋体2,2,2-三氟-1-(萘基)乙醇(TFNEs)的光学分辨率是通过在正庚烷中用脂肪酶催化的对映选择性醋酸化实现的,得到S-醋酸酯和R-醇。将甲基引入萘环的4位(2b)或2位(2c)显著降低了反应活性,特别是对于2c。2,2,2-三氟-1-(1-萘基)乙醇(2a)与其区域异构体2,2,2-三氟-1-(2-萘基)乙醇(2d)表现出不同的行为:脂肪酶[LIP(假单胞菌)、PLC(阿尔卡利菌)和ALC(嗜色菌)]对2a的对映选择性较高,但对2d较低,而脂肪酶[AK和PS(假单胞菌)]对2d的选择性高于对2a。还合成了另外三个衍生物,2,2,2-三氟-1-(苯基)乙醇(2e)、2,2,2-三氟-1-(吲哚-3-基)乙醇(2f)和1-(1-萘基)乙醇(2g),并将它们在脂肪酶催化的醋酸化中的表现与2a进行了比较。