| abstract |
PURPOSE: To readily obtain a compound having difluoromethylene group in high yield and selectivity, by treating a carbonyl compound in an acylalating and fluorinating steps and substituting oxygen atom. of the carbonyl group with 2 fluorine atoms. n CONSTITUTION: A carbonyl compound expressed by formula I (R and R' are H, aliphatic, alicyclic, aliphatic-aromatic or aromatic group) (e.g., cyclopentanone except unsubstituted cyclohexanone) is reacted with a perfluoroalkylcarboxylic acid anhydride expressed by formula II (Rf is perfluoroalkyl group) to provide an acylal compound, expressed by formula III and containing perfluoroalkylcarbonyloxy groups (acylalating step). The resultant compound is then reacted with hydrogen fluoride to afford the aimed compound, expressed by formula IV and having difluoromethylene group (e.g., 1,1-difluorocyclopentane) and a perfluoroalkylcarboxylic acid (fluorinating step). Furthermore, the fluorinating step is preferably carried out in the presence of an acid catalyst. n COPYRIGHT: (C)1989,JPO&Japio |