Benzenoids in principle represent attractive and abundant starting materials for the preparation of substituted cyclohexanes. However, the synthetic tools available for overcoming the considerable aromatic energies inherent to these building blocks limit the available product types.
In a paper published in JACS, researchers in the Johnson Group demonstrate access to heretofore unknown heterotricyclic structures by leveraging oxidative dearomatization of 2-hydroxymethyl phenols with concurrent N-hydroxycarbamate dehydrogenation using a common oxidant. The pairwise-generated, mutually reactive species then participate in a second stage acylnitroso Diels–Alder cycloaddition. The reaction chemistry of the derived [2.2.2]-oxazabicycles, bearing four orthogonal functional groups and three stereogenic centers, is shown to yield considerable diversity in downstream products.
The methodology presented allows for the expeditious synthesis of a functionalized intermediate bearing structural and stereochemical features in common with the complex alkaloid tetrodotoxin.