Oxidative 1,2- and 1,3- alkyl shifts mediated by a hypervalent iodine reagent were performed on simple and inexpensive phenol derivatives. These transpositions enable rapid redesign of the main aromatic skeleton to generate good yields of highly functionalized scaffolds containing a prochiral dienone system, a quaternary carbon center connected to as many as four sp(2) centers, and a carbonyl functionality or precursor. An efficient enantioselective version of this process resulting in the formation of a challenging quaternary carbon center is also described. The products represent the central cores of several natural products having important bioactivities. As an illustration of the potential of this method, we describe the rapid synthesis of several functionalized polycyclic systems as well as a formal synthesis of acetylaspidoalbidine, a hexacyclic alkaloid belonging to the Aspidosperma family.

An oxidative Wagner-Meerwein transposition involving different functionalities mediated by a hypervalent iodine reagent has been accomplished. The strategy fits within the concept of "aromatic ring umpolung" and allows rapid access to highly functionalized cores.

A concise total synthesis of (+/-)-aspidospermidine has been achieved in twelve steps from inexpensive 4-ethylphenol, based on an oxidative Hosomi-Sakurai reaction via the concept of "aromatic ring umpolung".

An oxidative Prins-pinacol tandem process mediated by a hypervalent iodine reagent has been developed. This oxidative version of the famous tandem process fits within the concept of "aromatic ring umpolung" and allows the stereoselective transformation of simple phenols into highly elaborated spirocyclic dienone cores containing several quaternary carbon centers. The scope and the limitations of this process, including the study of its stereoselectivity, are described in this article. As a direct application of this stereoselective process, we describe the formal synthesis of (-)-platensimycin, an important antibiotic agent.

No abstract