Different tributyltin phenoxides react at room temperature with ethyl propiolate in benzene, in the presence of tin(IV) chloride, triethylamine and their mixture to give the derivatives of 3-phenoxyacrylic acid ethyl ester. Exceptionally, 3-(2-hydroxyphenyl)acrylic acid ethyl ester and 3-(2-hydroxy-5-methylphenyl)acrylic acid ethyl ester have been obtained from the reaction of tributylphenoxytin and tributyl(p-tolyloxy)tin, respectively catalysed by SnCl 4 , and they have been easily hydrolysed to coumarin and 6-methylcoumarin.