A palladium-catalyzed intramolecular decarboxylative cyclization of α-aryl-γ-methylidene-δ-valerolactones, followed by olefin isomerization, has been developed to give fused polycyclic aromatic compounds under mild conditions. The process described here can be regarded as a formal decarboxylative allylic arylation without using a pre-formed organometallic nucleophile. The reaction can be conducted on a gram scale and the products thus obtained are further derivatized with ease.
subsequent boron-trifluoride etherate catalyzed methanolysis of the resultant carbinol acetals . Treatment of α-acetylketene dithioacetals and with methylmagnesiumiodide afforded the carbinol acetals and respectively which under above sequence of reactions yielded the corresponding α-isopropylidene-γ-butyrolactones and in good yields.
Facile synthesis of lactones and dihydronaphthalenes from methyl 2-isobutenyl (or 2-isopentenyl)cinnamates as the common intermediates
作者:Saravanan GowriSankar、Chang Gon Lee、Jae Nyoung Kim
DOI:10.1016/j.tetlet.2004.07.070
日期:2004.9
We prepared three different types of compounds, two α-alkylidene-γ-butyrolactones and 3,4-dihydronaphthalene-2-carboxylic acid from methyl 2-isobutenylcinnamates or methyl 2-isopentenylcinnamates as the common intermediates, which were derived from the acetates of Baylis–Hillman adducts.