Trifluoromethanesulfonicacid in acetonitrile was found to efficiently catalyze Friedel–Crafts alkylations of 1,2,4-trimethoxybenzene with a variety of simple or functionalized aldehydes to provide di- or triarylmethanes in high yields. The operationally simple protocol allowed a short synthesis of the phenylpropanoid natural product (−)-tatarinoid C establishing its absolute configuration. Under the