The acid-catalyzed ring closure of 2, 2'-dihydroxybiphenyls to corresponding dibenzofurans has been studied using various acid catalysts.” However, these methods require elevated temperatures (> 350 “C), long reaction times, and an excess of protic and Lewis acids. Furthermore, some of these reactions were plagued with undesirable side products during cyclization.'Therefore, the scope and selectivity for the preparation of dibenzofuran ...
