The present invention relates to a process for making indenol esters or ether from an α-substituted cinnamic aldehyde derivative such as an acetal or an acylal. This reaction is promoted by the use of strong mineral acids, sulphonic acids, acidic zeolites or Lewis acids.
Conversion of 2-Alkylcinnamaldehydes to 2-Alkylindanones via a Catalytic Intramolecular Friedel−Crafts Reaction
作者:Gary B. Womack、John G. Angeles、Vincent E. Fanelli、Christie A. Heyer
DOI:10.1021/jo070952o
日期:2007.8.31
3-arylpropanoic acids or halides requires the use of noncatalytic acid promoters. In the presence of 5−10 mol % FeCl3, in situ generated dimethyl acetals of (E)-2-alkylcinnamaldehydes cyclize to 1-methoxy-2-alkyl-1H-indenes in good-to-high yields. The 1-methoxyindenes were converted in high yield into 2-alkylindanones by treatment with triethylamine, to effect isomerization to the isomeric enol ethers