亚胺离子
环加成
化学
丙炔
烯醇
环丁烯
亲核细胞
亲核加成
有机化学
烯醇醚
药物化学
戒指(化学)
催化作用
作者
Philipp Kratzer,Holger Gerster,Gerhard Maas
出处
期刊:Synthesis
[Georg Thieme Verlag KG]
日期:2015-08-04
被引量:6
标识
DOI:10.1055/s-0034-1380223
摘要
Acetylenic iminium salts (propyne iminium salts) react with cyclic enol ethers in a thermal [2+2] cycloaddition reaction to afford condensed cyclobutene iminium salts. With acyclic enol ethers, a cycloaddition/electrocyclic ring-opening sequence occurs to give (1-alkoxybuta-1,3-dien-2-yl)methane iminium salts as mixtures of diastereoisomers. An analogous scenario is observed with 5-phenyl-2-vinylfuran as the nucleophilic olefinic component. With 1-methoxy-3-trimethylsilyloxy-1,3-butadiene, propyne iminium salts undergo a [4+2] cycloaddition. For all reactions, traces of acid must be quenched with solid K2CO3 or CaO to avoid immediate polymerization of the enol ether.
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