Indanones and Indenols from 2-Alkylcinnamaldehydes via the Intramolecular Friedel−Crafts Reaction of Geminal Diacetates
摘要:
When treated with Ac(2)O at rt in the presence of 4-6 mol% FeCl(3), 2-alkylcinnamaldehydes are converted to 2-alkyl-1H-inden-1-yl acetates through the intermediacy of gemdiacetates. Methanolysis of the indenyl acetates yields the corresponding indenols, Saponification yields 2-alkylindanones, providing, in effect, an intramolecular acylation employing catalytic levels of acid.
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.
Indanones and Indenols from 2-Alkylcinnamaldehydes via the Intramolecular Friedel−Crafts Reaction of Geminal Diacetates
作者:Gary B. Womack、John G. Angeles、Vincent E. Fanelli、Brinda Indradas、Roger L. Snowden、Philippe Sonnay
DOI:10.1021/jo900910b
日期:2009.8.7
When treated with Ac(2)O at rt in the presence of 4-6 mol% FeCl(3), 2-alkylcinnamaldehydes are converted to 2-alkyl-1H-inden-1-yl acetates through the intermediacy of gemdiacetates. Methanolysis of the indenyl acetates yields the corresponding indenols, Saponification yields 2-alkylindanones, providing, in effect, an intramolecular acylation employing catalytic levels of acid.