On the stereochemical outcome of the reaction between (–)-chorismic acid and diazomethane: absolute proof of stereochemistry of the major pyrazoline by X-ray crystallography of a cyclopropane based derivative
作者:Harry Adams、Neil A. Bailey、Martyn Frederickson、Edwin Haslam、Gareth M. Davies、David A. Jude
DOI:10.1039/p19960001531
日期:——
afforded a pair of cyclopropane derivatives with stereochemistry that could not be confidently assigned using data from coupling constants alone. NOE data allowed a more confident assignment of the stereochemistry of the two cyclopropanes; the β-cyclopropyl derivative was saponified and hydrolysed to yield a bicyclo[4.1.0]hept-2-ene-1-carboxylic acid derivative that was unequivocally shown to possess (1S,4R
重新研究(-)-癸二酸与重氮甲烷在乙醚中的反应的大规模研究表明,先前报道的单吡唑啉基产物伴随有立体异构体,该立体异构体是由重氮甲烷添加到更受阻的α-面中而产生的。分支酸1,2-双键(α:β加成约1:6)。两个环加合物在80°C的温度下热解,得到一对具有立体化学结构的环丙烷衍生物,仅凭耦合常数的数据无法确定该对衍生物的位置。NOE数据可以更可靠地确定两个环丙烷的立体化学。将β-环丙基衍生物皂化并水解,得到双环[4.1.0]庚-2-烯-1-羧酸衍生物,该衍生物明确显示具有(1 SX射线晶体学研究得到了,4 R,5 R,6 R)-立体化学。