| abstract |
Alkenes of the formula (I):n in which R is C 2-6 alkyl, n is 1, 2 or 3 and X, independent of other substituents X, is a specified substituent preferably chloro or fluoro, are prepared by reacting a compound of formula (III):n with methylenetriphenylphosphorane or by dehydrating an alcohol of formula (V):n especially by heating the alcohol (V) in the presence of an alumina catalyst. n The alkenes are useful intermediates for the synthesis offungicidal compounds. |