Tandem InCl-Promoted Hydroperoxide Rearrangements and Nucleophilic Additions: A Straightforward Entry to Benzoxacycles.

The acid-catalyzed rearrangement of organic peroxides is generally associated with C-C-bond cleavages (Hock and Criegee rearrangements), with the concomitant formation of an oxocarbenium intermediate. This article describes the tandem process between a Hock or Criegee oxidative cleavage and a nucleophilic addition onto the oxocarbenium species (in particular a Hosomi-Sakurai-type allylation), under InCl catalysis. It was applied to the synthesis of 2-substituted benzoxacycles (chromanes and benzoxepanes), including a synthesis of the 2-(aminomethyl)chromane part of sarizotan, and a total synthesis of erythrococcamide B.