Kinetic resolution of primary 2-methyl-substituted alcohols via Pseudomonas cepacia lipase-catalysed enantioselective acylation
作者:Ove Nordin、Ba-Vu Nguyen、Carin Vörde、Erik Hedenström、Hans-Erik Högberg
DOI:10.1039/a908023f
日期:——
The enantioselectivities of lipases from Pseudomonas cepacia (PFL, Amano PS, etc.) towards a series of primary 2-methyl-substituted alcohols using vinyl acetate as the acyl donor in transesterifications in organic solvents were studied. In terms of enantioselectivity, the best results were found for 3-aryl-2-methylpropan-1-ols with enantiomeric ratios (E-values) over 100 in most cases, whereas other 3-substituted primary 2-methylpropan-1-ols generally displayed lower enantioselectivities: 3-cycloalkyl-2-methylpropan-1-ols (E ≈ 20) and 2-methylalkan-1-ols (E ≈ 10). Moving the aryl group closer or further away from the chiral centre resulted in low enantioselectivities: 2-arylpropan-1-ols (E < 10), 2-methyl-4-(2-thienyl)butan-1-ol (E = 12), 2-methyl-5-(2-thienyl)pentan-1-ol (E = 3.2) and 2-methyl-6-(2-thienyl)hexan-1-ol (E = 3.8).
研究了来自洋葱伯克霍尔德菌(Pseudomonas cepacia)的脂肪酶(如PFL、Amano PS等)在对一系列一级2-甲基取代醇使用乙酸乙烯酯作为酰基供体进行有机溶剂中的转酯化反应时的对映选择性。在对映选择性方面,最佳结果出现在3-芳基-2-甲基丙-1-醇中,大多数情况下对映体比例(E值)超过100,而其他3-取代的一级2-甲基丙-1-醇通常显示出较低的对映选择性:3-环烷基-2-甲基丙-1-醇(E ≈ 20)和2-甲基烷-1-醇(E ≈ 10)。将芳基团更靠近或远离手性中心会导致低对映选择性:2-芳基丙-1-醇(E < 10)、2-甲基-4-(2-噻吩基)丁-1-醇(E = 12)、2-甲基-5-(2-噻吩基)戊-1-醇(E = 3.2)和2-甲基-6-(2-噻吩基)己-1-醇(E = 3.8)。