5-(1-Ethyl-propenyl)-3-methyl-benzofuran-2-carboxylic acid ethyl ester 、
邻甲酚 、
trifluoroborane diethyl ether 以to give the title compound (4.04 g, 91%)的产率得到5-[1-ethyl-1-(4-hydroxy-3-methyl-phenyl)-propyl]-3-methyl-benzofuran-2-carboxylic acid ethyl ester