Abstract: As a process for preparing a compound of the formula ##STR1## in which both Rs are H or --OH comprising the steps: a. of treating the ethyl ester of caffeic acid with a trialkylsilyl chloride at ambient conditions in equimolar proportions in the presence of a base;b. of reduction of the resulting product with an aluminium hydride reagent at sub-zero temperature and equimolar proportions to yield the corresponding allylic alcohol;c. of halogenation of this allylic alcohol with thionyl chloride or a phosphorus trihalide to yield the corresponding allyl halide;d. of coupling this allyl halide with the silyl ether of compound of the formula ##STR2## in refluxing ether solutions; and e. of hydrolysis of this coupled product with tetra alkyl ammonium flouride at ambient conditions and of equimolar proportions.

Abstract: A process for preparing a compound of the formula ##STR1## in which both Rs and H or OH; comprising the steps a. of treating the ethyl ester of caffeic acid with trialkylsilyl chloride at ambient conditions in equimolar proportions in the presence of a base;b. the reduction of the ester to the corresponding allylic alcohol with aluminum hydride reagent;c. of oxidizing the resulting product with manganese dioxide at ambient temperature and in excess molar proportion to yield the corresponding allylic aldehyde;d. of coupling the latter with the silyl ether of the relative phenyl acetylide; ande. of hydrolysis of this coupled product with alkylammonium fluoride at ambient conditions in equimolar proportions.