TMSOTf-mediated reactions of 2-aryl-1-(1-phenylcyclopropyl) ethanones 1 with allenic esters afford a novel method for the synthesis of 6-methyl-3a, 7-diaryl-3, 3a-dihydro-2 H- benzofuran-4-one derivatives 2 in moderate yields. In addition, we also found that TMSOTf- mediated reactions of 1-cyclopropyl-2-arylethanones with ethyl acetoacetate can provide the corresponding 2, 3-dihydrobenzofuran-4-ol and dihydrofuro [2, 3-h] chromen-2-one in ...