Reversible Cyclopropane Ring-Cleavage Reactions within etheno-bridged [4.3.1]propelladiene frameworks leading to aza- and oxa-[5.6.5.6] fenestratetraenes

Abstract

Opening and closing a chemical window: Oxidation of the etheno-bridged [4.3.1]propelladienol 1 with pyridinium chlorochromate (PCC) affords oxa[5.6.5.6]fenestratetraene 2. The reduction of 2 with diisobutylaluminum hydride (DIBAl-H) leads to the regeneration of its precursor (1; see scheme). These transformations most likely involve a [3,5]-sigmatropic rearrangement process.