Highly stereoselective tandem cyclizations of 5-hexenyllithiums: preparation of endo-2-substituted bicyclo[2.2.1]heptanes and 3-substituted trans-bicyclo[3.3.0]octanes
作者:William F. Bailey、Atmaram D. Khanolkar、Kaustubh V. Gavaskar
DOI:10.1021/ja00047a013
日期:1992.10
diolefinic alkyl iodides by low-temperature lithium-iodine exchange, proceeds via two highly stereoselective and totally regiospecific 5-exo-trig ring closures to deliver bicyclic alkyllithiums. Trapping of the organolithium product by addition of an electrophile cleanly affords functionalized bicyclic molecules in good yield. In this way both endo-2-substituted bicyclo[2.2.1]heptanes and 3-substituted
通过低温锂碘交换衍生自无环二烯烷基碘的二烯烷基锂的串联环化,通过两个高度立体选择性和完全区域特异性的 5-exo-trig 闭环进行,以提供双环烷基锂。通过添加亲电子试剂捕获有机锂产物,可以以良好的收率干净地提供功能化的双环分子。以这种方式,内-2-取代的双环[2.2.1]庚烷和3-取代的反-双环[3.3.0]辛烷均以65-80%的分离产率从容易获得的3-(2-碘乙基) )-1,5-己二烯 (5) 和 7-iodo-4-ethenyl-1-heptene (9),分别