An intramolecular Diels-Alder (IMDA) reaction efficiently accelerated by Schreiner's thiourea is reported, to build a functionalized cytochalasin scaffold (periconiasin series) for biological purposes. DFT calculation highlighted a unique multidentate cooperative hydrogen bonding in this catalysis. The deprotection end game afforded a collection of diverse structures and showed the peculiar reactivity of the Diels-Alder cycloadducts upon functionalization. Biological studies revealed strong cytotoxicity of a few compounds on breast cancer cell lines while actin polymerization is preserved.

The acid-catalyzed rearrangement of organic peroxides is generally associated to C-C-bond cleavages (Hock and Criegee rearrangements), with the concommittent 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 Sakurai-Hosomi-type allylation), under InCl3 catalysis. It was applied to the synthesis of 2-substituted benzoxacycles (chromanes, benzoxepanes), including a synthesis of the 2-(aminomethyl)chromane part of sarizotan, and a total synthesis of erythrococcamide B.