Chemoenzymatic Approach to Enantiomerically Pure (<i>R</i>)-3-Hydroxy-3-methyl-4-pentenoic Acid Ester and Its Application to a Formal Total Synthesis of Taurospongin A
作者:Aya Fujino、Takeshi Sugai
DOI:10.1002/adsc.200800191
日期:2008.8.4
(R)-3-Hydroxy-3-methyl-5-hexanoic acid p-methoxybenzyl ester 1b was prepared by carbon-chain elongation on both termini of the starting material, (R)-3-benzyloxy-2-methylpropane-1,2-diol 2a, which was prepared by an over-expressed Bacillus subtilis epoxide hydrolase-catalyzed enantioselective hydrolysis of the racemic 1-benzyloxymethyl-1-methyloxirane 3. One of the key steps of the requisite transformation
(R)-3-羟基-3-甲基-5-己酸对甲氧基苄酯1b是通过在原料(R)-3-苄氧基-2-甲基丙烷-1的两个末端上进行碳链延伸而制备的, 2-二醇2a,是由过量表达的枯草芽孢杆菌环氧化物水解酶催化的外消旋1-苄氧基甲基-1-甲基环氧乙烷3的对映选择性水解。必需转化的关键步骤之一是在中性条件下,红球红球菌NBRC 15564介导的氰基水解为羧基,以排除中间体和/或产物的任何外消旋作用。()的对映体纯形式R)-1b被用于牛磺pongin A的新的正式全合成。