BCl3-promoted synthesis of benzofurans

Lewis acidic nature of boron trichloride (BCl3) to coordinate to the carbonyl functionality was exploited for the synthesis of benzofurans via dehydrative cyclization. This mild and efficient procedure allowed for facile access to a number of highly substituted benzofurans in a regioselective manner. The structural requirement for the successful cyclodehydration was examined in the cases, where competitive demethylation could occur.