1-(1-Hydroxy-2-trimethylsilylmethylprop-2-enyl)-2-(4-methoxybut-3enyl)-4-methoxybenzene, prepared by a short synthesis, underwent (3 + 2) cycloaddition to form predominantly the cis-fused tricycle 3,7-dimethoxy-1-methylene-2,3,3a,4,5,9b-hexhydro-1H-benz[e]indene upon treatment with TiCl4 or triflic anhydride.