Enantioselektive synthese von isobutenyl-cyclobutancarbonsäuren als vierring—analoga zur chrysanthemumsäure—II
作者:H.-D. Scharf、H. Kalkoff、J. Janus
DOI:10.1016/0040-4020(79)88014-x
日期:1979.1
The enantiomers of 2,2-dimethyl-3-cis-(2'-methylpropenyl)-cyclobutane-1-carboxylic acids (4 and 4') and 2,2-dimethyl-3-trans-(2'-methylpropenyl)-cyclobutane-1-carboxylic acids (10 and 10') were synthesized m optically pure state. Starting from (−)-α-pinene (14) resp. (+)-α-pinene (14') 2,2-dimethyl-3-cis-formyl-cyclobutane-1-car-boxylic acid methylester (21 and 21') was received in an enantioselective
2,2-二甲基-3-顺-(2'-甲基丙烯基)-环丁烷-1-羧酸(4和4 ')和2,2-二甲基-3-反-((2'-甲基丙烯基)-环丁烷-1-羧酸(10和10 “)的合成米光学纯状态。从(-)-α-pine烯(14)开始。(+)-α-pine烯(14 ')2,2-二甲基-3-顺式-甲酰基-环丁烷-1-羧基羧酸甲酯(21和21 ')以对映选择性途径被接收并通过酸催化异构化为2,2-二甲基-3-反式-甲酰基-环丁烷-1-羧酸甲酯(23和23 ')。在随后的维蒂希反应中,将4个醛酯21、21',23和23 '转化为异丁烯基-环丁烷-羧酸甲酯的对映异构体,并通过间苯氧新泻醇进行酯化。水解为异丁烯基-环丁烷-羧酸。