研究了几种导致非对映异构的二仲1,4-二醇及其1,4-二磺酸酯消除环化的方法,这些方法导致形成四氢呋喃,并发现它们均通过S N 2型机理进行立体选择,在一个(1,4-二醇)或两个(1,4-二磺酸酯)手性中心构型反转,因此内消旋(即赤型)1,4-二醇和±(即苏式)1,4-二甲磺酸酯仅提供反式-2,5-二烷基四氢呋喃,而相应的非对映异构底物仅转化为顺式-2,5-二烷基四氢呋喃。
Asymmetric synthesis of trans-2,5-dimethylpyrrolidine
作者:Mariel E. Zwaagstra、Auke Meetsma、Ben L. Feringa
DOI:10.1016/s0957-4166(00)80066-x
日期:1993.10
A new synthetic route to (2S,5S)-dimethylpyrrolidine 1, which can also be applied to the synthesis of the (2R,5R)-enantiomer, has been developed. The C2-symmetric pyrrolidine can be obtained enantiomericallypure (e.e. ⩾ 97%) in 15% overall yield starting from a mixture of isomers of 2,5-hexanediol, via a short reaction sequence using (S)-α-methylbenzylamine as a chiral auxiliary. The crystal and molecular
已开发出一种新的合成路线,以合成(2S,5S)-二甲基吡咯烷1,该路线也可用于合成(2R,5R)-对映体。以2,5-己二醇的异构体混合物为原料,经短时间的反应,使用(S)-α-甲基苄胺作为对映体,可以以15%的总收率获得对映体纯的C 2对称吡咯烷(ee ee 97%)。手性助剂。还报道了(S)-2'-苯基-N-乙基-(2S,5S)-二甲基吡咯烷苦味酸盐5的晶体和分子结构,其显示了苦味酸盐单元的反平行堆叠。
Derivatives of 2,3-anhydro-dl-threitol, 2,3:4,5-dianhydrogalactitiol, and 2,3:4,5-dianhydroallitol
作者:Géza Schneider、Tibor Horváth、Pál Sohár
DOI:10.1016/s0008-6215(00)84235-4
日期:1977.6
alpha, omega-Disubstituted derivatives of 2,3-anhydro-DL-threitol (2), 2,3-anhydroerythritol (4), 2,3:4,5-dianhydrogalactitol (8), and 2,3:4,5-dianhydroallitol (12) have been synthesised by epoxidation of the appropriate alkeness and dienes. Benzyloxy carbonyl groups were used for protecting the primary hydroxyl groups during epoxidation.