Fluorinative Rearrangements of Substituted Phenylallenes Mediated by (Difluoroiodo)toluene: Synthesis of α-(Difluoromethyl)styrenes.

Phenylallenes undergo fluorinative rearrangement upon the action of (difluoroiodo)toluene in the presence of 20 mol % BF3 ⋅OEt2 to yield α-difluoromethyl styrenes. This unprecedented reaction was entirely chemoselective for the internal allene π bond, and showed remarkable regioselectivity during the fluorination event. Substituted phenylallenes, phenylallenes possessing both phenyl- and α-allenyl substituents, and diphenylallenes were investigated, and good functional-group compatibility was observed throughout. The ease with which allenes can be prepared on a large scale, and the operational simplicity of this reaction allowed us to rapidly access fluorine-containing building blocks that have not been accessed by conventional deoxyfluorination strategies.

Arylation of diorganochalcogen compounds with diaryliodonium triflates: metal catalysts are unnecessary.

Diaryliodonium triflates transfer an aryl group to the chalcogen atom of organic sulfides, selenides, and tellurides (but not ethers), in the absence of transition-metal catalyst, simply upon heating in chloroform or dichloroethane solution.

Iodonium metathesis reactions.

A metathesis reaction occurs when a diaryliodonium triflate is heated with an aryl iodide, resulting in the formation of a new diaryliodonium triflate.

Oxidative Friedel-Crafts reaction and its application to the total syntheses of Amaryllidaceae alkaloids.

An oxidative Friedel-Crafts reaction involving different aromatic compounds mediated by a hypervalent iodine reagent has been performed, using polysubstituted phenols. The strategy fits within the concept of "aromatic ring umpolung", which opens up novel opportunities in chemical synthesis. The reaction takes place in useful yields, and allows rapid access to highly functionalized compounds containing a dienone, a quaternary carbon center, and an aromatic ring. The product's skeleton is present in numerous natural products. As an illustration of the potential of this transformation, total syntheses of compounds belonging to the Amaryllidaceae alkaloids family such as O-methyljoubertiamine, mesembrine, and its natural derivative the dihydro-O-methylsceletenone have been achieved in eight/nine steps. The synthetic route to these molecules features a novel and efficient transformation on the basis of a Fukuyama and Michael-retro-Michael tandem process to produce the required nitrogen-containing ring system.