作者:P. Caramella、T. Bandiera、P. Grünanger、F. Marinone Albini
DOI:10.1016/s0040-4020(01)91194-9
日期:1984.1
Cycloadditions of nitrile oxides to 2,3-dihydrofuran are highly regioselective whereas the regioselectivity of the cycloadditions to 2,3-dihydrothiophen is only moderate. The directing effect of oxygen and sulfur in these cycloadditions could be evaluated at 2.8 and 1.1 Kcal mol-1 respectively. The related acyclic sulfur dipolarophiles, (E)-propenyl methyl and phenyl sulfides, similarly undergo cycloadditions
腈氧化物对2,3-二氢呋喃的环加成反应具有很高的区域选择性,而对2,3-二氢噻吩的环加成反应的区域选择性仅适中。在这些环加成反应中,氧和硫的定向作用可以分别在2.8和1.1 Kcal mol -1下评估。相关的无环硫双极性亲和剂((E)-丙烯基甲基和苯基硫化物)同样以中等区域化学方式进行环加成反应。