A Novel Synthesis of Methylenecyclopropane Spiro-Linked with Cycloalkanes via a Cyclization of Allylic Epoxides and Its Application to a Synthesis of Fused 3-Methylfurans
作者:Tsuyoshi Satoh、Yasushi Kawase、Koji Yamakawa
DOI:10.1246/bcsj.64.1129
日期:1991.4
Ring closure of allylicepoxides derived from 1-chloroalkyl phenyl sulfoxides and cyclic ketones with lithium diisopropylamide (LDA) in 3-Exo-Tet mode gave spiro-linked methylenecyclopropanes having a hydroxyl group in good yields. Oxidation of these compounds gave ketones, which were then treated with p-toluenesulfonic acid in 1,4-dioxane or DMSO at 100°C to give fused 3-methylfurans in good overall
A novel synthesis of carbocyclic spiro-type methylenecyclopropane derivatives
作者:Tsuyoshi Satoh、Yasusht Kawase、Koji Yamakawa
DOI:10.1016/s0040-4039(00)94456-3
日期:1990.1
A novel method is described for the synthesis of carbocyclic spiro-type methylenecyclopropane derivatives via the cyclization of allyl-epoxides, which are readily available from ketones and 1-chloroalkyl phenyl sulfoxides.
The aldols are synthesized from three compoments (1-chloroalkyl phenyl sulfoxide and two kinds of carbonyl compounds and ) through α,β-epoxy sulfoxides using lithiumdimethylcuprate as an electron-transfer reagent.
Lithium-chlorine exchange of α-chloro α-sulfonyl ketones, easily prepared from 1-chloroalkyl aryl sulfoxides and aldehydes in good yields, with n-butyllithium gave α-sulfonyl ketones in high yields. Some trials to trap the enolate intermediate were carried out.