Bioreduction of α-Acetoxymethyl Enones: Proposal for an S<sub>N</sub>2′ Mechanism Catalyzed by Enereductase
作者:Bruno R. S. Paula、Davila Zampieri、J. Augusto R. Rodrigues、Paulo J. S. Moran
DOI:10.1002/adsc.201600601
日期:2016.11.17
acylated Morita–Baylis–Hillman adduct 1‐acetoxy‐2‐methylene‐1‐phenylbutan‐3‐one produced a mixture of products, with and without the acetoxy group, via three different reaction pathways. In addition to experiments employing whole cells, those in which isolated enereductases were used suggested that the main pathway through which the loss of the acetoxy group occurs during the biocatalytic cascade is an SN2′‐type
(Z)-3-乙酰氧基甲基-4-R-3-丁烯-2-酮(R =芳基,烷基)和(Z)-3-甲基-4-R-3-丁烯-2-丁烯(R =芳基)合成并通过酿酒酵母进行还原,分别产生(R)-和(S)-4-R-3甲基丁烷-2-。这种立体化学控制策略适用于对映体过量至中度过量的(R)-和(S)-Tropional®的合成。其他(Z)-3-酰氧基甲基-4-苯基-3-丁烯-2-酮的行为与(Z)-3-乙酰氧基甲基对应物和酰化的Morita-Baylis-Hillman加合物1-乙酰氧基-2-亚甲基-1-苯基丁烷-3-酮通过三种不同的反应途径生成了带有或不带有乙酰氧基的产物混合物。除了使用全细胞的实验外,使用分离的烯还原酶的实验还表明,在生物催化级联反应中发生乙酰氧基丢失的主要途径是S N 2'型反应,而不是正式的氢加成反应。消除乙酸。最后,相关的乙基烯酮被酵母白色念珠菌对映体选择性还原,产生(R)-和(S)还原产物,取决于起始原料中乙酰氧基的存在。