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.
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.
The intersection between the chemistries of hypervalent iodine (HVI) reagents and organophosphorus compounds holds significant potential. To date, the merging of these research spheres has led to novel iodane motifs, many of which have been used in new oxyphosphorylation methodologies. In addition, HVI reagents have proven easily capable of transferring electrophilic carbon-based (alkyl, aryl, al-kynyl, etc.) ligands to various phosphorus nucleophiles. Furthermore, the ease with which HVI reagents oxidize phosphorus has led to novel esterification, amidation, alcohol functionalization and peptide coupling reactions. This Focus Review summarizes the chemistry to-date between these two important classes of compounds. Scheme 1. General reactivity modes of l 3 -iodanes.[a] Dr.Scheme 2. Phosphorus-containing HVI reagents.Scheme 3. ortho-Stabilized HVI reagents. Scheme 4. Phosphorus-containing HVI reagents generated in situ. Scheme 5. Synthesis of alkynyl phosphate esters. Scheme 6. Oxyphosphorylation of vinyliodonium salts. Scheme 10. Synthesis of a-carbonyl phosphonates and phosphinates. Scheme 11. Synthesis of a-carbonyl phosphonates. Scheme 12. Synthesis of a-carbonyl phosphonates via in situ-generated 26. Scheme 13. Synthesis of tris-ketol phosphates. Scheme 19. Phosphorylation of silylenol ethers. Scheme 20. Preparation of phosphonates by arylation of phosphites. Scheme 21. Arylation of PÀH phosphine oxides and phosphonates. Scheme 22. Synthesis of bis(triphenylphosphonium) salts. Scheme 23. Phosphorylation of alkynyliodonium salts with phosphites. Scheme 28. Synthesis of vinyl phosphonates from vinyl iodonium salts. Scheme 30. Trifluoromethylation of naphthyl-derived phosphines. Scheme 29. Trifluoromethylation of phosphines. Scheme 35. Peptide coupling mediated by PPh 3 and 200 or 217.Scheme 36. Synthesis of acyl and alkyl chlorides, and alkyl fluorides using 207 and 208 generated in situ.Scheme 37. Synthesis of mixed iodonium phosphonium ylides.
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