presence of a catalytic amount of a rhenium or manganese complex gives ring‐expanded and carbon‐chain extension products, respectively. In these reactions, alkynes insert into a non‐strained carbon–carbonsinglebond of 1,3‐dicarbonyl compounds. The ring‐expansion reaction is also promoted by the addition of 4‐Å molecular sieves instead of a catalytic amount of an isocyanide.
Iron(III)-Catalyzed Conia–Ene Cyclization of 2-Alkynic 1,3-Dicarbonyl Compounds
作者:Li Yan Chan、Sunggak Kim、Youngchul Park、Phil Ho Lee
DOI:10.1021/jo300957q
日期:2012.6.15
A cheap, simple, and effective FeCl3-catalyzed Conia–ene cyclization of 2-alkynic 1,3-dicarbonyl compounds was stereospecific to afford alkylidenecyclopentanes in (E)-isomers via the 5-exo-dig pathway. The 5-endo-dig and 6-exo-dig cyclizations were also possible, depending on the structure of the substrates.