Generation of Acyloxyketenes from Unstable Mesoionic 1,3-Dioxolium-4-olates and Their Reaction with Ketenophiles To Give [2 + 2] Cycloadducts
作者:Masashi Hamaguchi、Naoki Tomida、Yuji Iyama、Takumi Oshima
DOI:10.1021/jo060074e
日期:2006.7.1
acyloxyphenylketenes was demonstrated by trapping the ketenes with several ketenophiles. Reactions of phenyldiazoacetic anhydride derivatives with several ketenophiles such as dihydrofuran, carbodiimides, and imines were carried out. No 1,3-dipolar cycloadducts of the latter with 1,3-dioxolium-4-olates were observed. Instead, only their [2 + 2]-cycloadducts with the acyloxyketenes generated by ring-opening of the initially
Rh 2(OAc)4生成的中离子1,3-二氧杂-4-醇盐的快速开环苯重氮基乙酸酐衍生物催化氧化分解为酰氧基苯基酮烯的方法是,用几种酮体亲和剂捕获烯酮,从而证明了这一点。进行了苯基重氮乙酸酐衍生物与几种亲酮体的反应,例如二氢呋喃,碳二亚胺和亚胺。没有观察到后者与1,3-二氧杂-4-醇盐的1,3-偶极环加合物。取而代之的是,仅分离它们的[2 + 2]-环加成物与通过最初形成的1,3-二氧杂-4-醇盐的开环而生成的酰氧基乙烯酮。在与环戊二烯的反应中,与[2 + 2]-乙烯酮加合物一起形成了1,3-偶极环加合物与1,3-二氧杂-4-醇酸酯的主要产物。PM3计算2,5-二苯基-1的形成热 3-二氧戊环-4-油酸酯和相应的苯甲酰氧基苯基乙烯酮表明,开环的酰氧基乙烯酮为约。9 kcal / mol比相应的1,3-二氧杂-4-醇盐更稳定。