The use of 1,2-O-isopropylidene-α-d-xylofuranose as a chiral auxiliary in asymmetric cyclopropanation reactions
作者:José M. Vega-Pérez、Ignacio Periñán、Fernando Iglesias-Guerra
DOI:10.1016/j.tetasy.2009.02.062
日期:2009.5
1,2-O-isopropylidene-d-xylofuranose, as a chiral auxiliary, is described. The Simmons–Smith cyclopropanation reaction of the corresponding alkenylidene derivatives with CH2I2/ZnEt2, in different reaction conditions, took place with high stereoselectivity. The diastereomeric excess in each case depended on the solvent and the temperature used in the reaction. The absolute configuration of the new stereogenic
描述了衍生自作为手性助剂的1,2 - O-异亚丙基-d-木呋喃糖的环丙基亚甲基缩醛的立体选择性合成。在不同的反应条件下,相应的链烯基衍生物与CH 2 I 2 / ZnEt 2的Simmons-Smith环丙烷化反应具有很高的立体选择性。在每种情况下,非对映异构体过量取决于反应中所用的溶剂和温度。通过手性助剂的环丙烷部分的酸水解确定了形成的新的立体异构中心的绝对构型,该手性助剂也被回收了。