Umpolung Strategy for Arene C–H Etherification Leading to Functionalized Chromanes Enabled by I(III) N-Ligated Hypervalent Iodine Reagents

Abstract

The direct formation of aryl C-O bonds via the intramolecular dehydrogenative coupling of a C-H bond and a pendant alcohol represents a powerful synthetic transformation. Herein, we report a method for intramolecular arene C-H etherification via an umpoled alcohol cyclization mediated by an I(III) N-HVI reagent. This approach provides access to functionalized chromane scaffolds from primary, secondary and tertiary alcohols via a cascade cyclization-iodonium salt formation, the latter providing a versatile functional handle for downstream derivatization. Computational studies support initial formation of an umpoled O-intermediate via I(III) ligand exchange, followed by competitive direct and spirocyclization/1,2-shift pathways.