The Catalyst-Controlled Regiodivergent Chlorination of Phenols

Different catalysts are demonstrated to overcome or augment a substrate's innate regioselectivity. Nagasawa's bis-thiourea catalyst was found to overcome the innate para-selectivity of electrophilic phenol chlorination, yielding ortho-chlorinated phenols that are not readily obtainable-via canonical electrophilic chlorinations. Conversely, a phosphine sulfide derived from 2,2'-Bis(diphenyl-phosphino)-1,1'-binaphthyl (BINAP) was found to enhance the innate para-preference of phenol chlorination.