作者:Sabine Laschat、Christine Hofmann、Angelika Baro
DOI:10.1055/s-2008-1077825
日期:——
The conjugate allylation of a homologous series of α,β-unsaturated cyclic esters 8-10 by addition of diallylcuprate (method A), fluoride ion catalyzed addition of trimethylallylsilane (method B), and aluminium tris(2,6-diphenylphenoxide) (ATPH)-mediated addition of allyllithium (method C) was investigated. Method A was not selective in all cases. For methods B and C an influence of ester moiety and ring size on the regioselectivity was observed. Methyl cyclopentenoate 8c gave mainly the 1,2/1,2-product regardless the allylation method while tert-butyl and benzyl ester moieties favored the 1,4-products. For larger rings 9, 10 and the anellated system 19 methods B and C behave complementary depending on the ester function: Method B gave best results of 1,4-addition products for benzyl esters while method C worked better for tert-butyl esters.
对同系物系列的α,β-不饱和环酯8-10进行了共轭烯丙基化研究,采用了不同的方法:双烯丙基铜盐的添加(方法A)、氟离子催化的三甲基烯丙基硅烷添加(方法B)以及铝三(2,6-二苯基苯氧基)(ATPH)介导的烯丙锂添加(方法C)。方法A在所有情况下都没有选择性。方法B和C则观察到了酯基团和环尺寸对区域选择性的影响。甲基环戊烯酸酯8c无论采用哪种烯丙基化方法,主要生成1,2/1,2产物,而叔丁基和苄基酯基团则更倾向于生成1,4产物。对于较大的环9、10以及环合系统19,方法B和C的效果互为补充,具体取决于酯功能:方法B对苯甲酯生成1,4-加成产物的效果最佳,而方法C则对叔丁基酯的效果更佳。