A nonenzymatic asymmetric reduction of ethyl benzoylformate with an achiral 1, 5-dihydro-5-deazaflavin derivative in chiral media was investigated as a model system for reruced nicotinamide adenine dinucleotide (phosphate)-dependent dihydrogenase. The chiral media include chiral nuclear magnetic resonance shift reagent, chiral Lewis acid, and a combination of metal ion an chiral ligand (additive). Of these reductions, a substantial asymmetric induction was observed in the presence of tris-[3-(heptafluoropropylhydroxymethylene)(+)-camphorato]europium to give ethyl mandelate possessing prediominantly S-configuration, in a optical yield of 24 to 36%. These values are among the highest so far reported in nonenzymatic reduction of ethyl benzoylformate with a 5-deazaflavin model. The discrimination of the prochiral face of the carbonyl compound was effectvie even when a catalytic amount of the chiral shift reagent was employed.
作为还原烟
酰胺腺嘌呤二
核苷酸(
磷酸盐)依赖性二
氢酶的模型系统,研究了在手性介质中用非手性 1, 5-二
氢-
5-脱氮黄素衍
生物对
苯甲酰甲酸乙酯进行非酶不对称还原。手性介质包括手性核磁共振位移试剂、手性
路易斯酸、以及
金属离子与手性
配体的组合(
添加剂)。在这些还原中,在三-[3-(七
氟丙基羟亚
甲基)(+)-
樟脑]
铕存在下观察到显着的不对称诱导,得到主要具有S-构型的
扁桃酸乙酯,光学产率为24%至36%。这些值是迄今为止报道的使用
5-脱氮黄素模型非酶法还原
苯甲酰甲酸乙酯的最高值之一。即使当使用催化量的手性位移试剂时,羰基化合物的前手性面的辨别也是有效的。