Efficient Synthesis of Enantiomerically Pure α-Alkyl Cyclopropanecarbonitrile Derivatives from Pyrazolines
作者:José L. García Ruano、Sergio A. Alonso de Diego、M. Rosario Martín、Esther Torrente、Ana M. Martín Castro
DOI:10.1021/ol047937f
日期:2004.12.1
[reaction: see text] Thermolysis of enantiopure sulfonyl pyrazolines 4 and 5, easily obtained from (Z)-3-p-tolylsulfinylacrylonitriles (1), afforded sulfonyl cyclopropanes (6, 7) in a completely stereoselective manner in almost quantitative yields. Both cyclopropanes and alkylidenecyclopropanes, containing one or two chiral carbon atoms, one of them being quaternary, were obtained by hydrogenolysis
[反应:见正文]对映体纯的对映体磺酰基吡唑啉4和5的热解很容易从(Z)-3-对甲苯基亚磺酰基丙烯腈(1)中获得,以几乎完全定量的方式,以完全立体选择性的方式提供了磺酰基环丙烷(6,7)。含有一个或两个手性碳原子的环丙烷和亚烷基环丙烷都分别通过CS键的氢解和在Julia报道的条件下获得。氮的高度立体选择性挤出表明存在协同作用的机理。