Iodobenzene and m-chloroperbenzoic acid mediated oxidative dearomatization of phenols

Oxidative dearomatization of 2- and 4-substituted phenols to their corresponding benzoquinone monoketals by catalytic amount of iodobenzene, and m-CPBA as a co-oxidant has been achieved via in situ generation of PhIO2, a hypervalent iodine(V) species. The transiently generated orthobenzoquinone monoketals further underwent Diels-Alder reaction with various dienophiles to furnish densely substituted bicyclo[2.2.2]octenones in high selectivities and yields. This methodology features ready availability of reagents, cost effectiveness, safety, brevity, selectivity, diversity and excellent yields. (C) 2016 Published by Elsevier Ltd.