There are many methods to construct benzofuran rings. The most typical methods are dehydration of phenoxyalkanone beneath acidic ailment,104 dehydration of o-hydroxybenzophenone under acidic issue,105 decarboxylation of o-acetylphenoxyacetic acid or ester less than alkaline ailment,106 and cyclization of o-hydroxybenzophenone to assemble benzofuran