Pseudocyclic Arylbenziodoxaboroles: Efficient Benzyne Precursors Triggered by Water at Room Temperature.

New organohypervalent iodine compounds, arylbenziodoxaborole triflates, were prepared from 1-acetoxybenziodoxaboroles and arenes by treatment with trifluoromethanesulfonic acid under mild conditions. Single crystal X-ray crystallography of these compounds revealed a pseudocyclic structure with a short intramolecular interaction of 2.698 to 2.717 Šbetween oxygen and iodine in the benziodoxaborole ring. These new pseudocyclic aryliodonium salts readily generate aryne intermediates upon treatment with water at room temperature. The generated aryne intermediates react with various substrates to give the corresponding aryne adducts in moderate to good yields. Furthermore, the new benzyne precursors can also work as arylating reagents towards aromatic rings. The aryne intermediates generated from arylbenziodoxaborole triflates selectively react with tert-butyl phenol forming products of ortho arylation in moderate yields.

Hypervalent iodine catalyzed generation of nitrile oxides from oximes and their cycloaddition with alkenes or alkynes.

Hypervalent iodine catalyzed oxidation of aldoximes using oxone as a terminal oxidant generates nitrile oxides, which react with alkenes and alkynes to give the corresponding isoxazolines and isoxazoles in moderate to good yields. This reaction involves active hypervalent iodine species formed in situ from catalytic iodoarene and oxone in the presence of hexafluoroisopropanol in aqueous methanol solution.

Hypoiodite mediated synthesis of isoxazolines from aldoximes and alkenes using catalytic KI and Oxone as the terminal oxidant.

Isoxazolines can be efficiently synthesized in good yields via a hypoiodite mediated catalytic oxidative cyclization of aldoximes and alkenes. This reaction involves active iodine species generated in situ from catalytic amounts of KI and Oxone.

Hypervalent iodine catalyzed Hofmann rearrangement of carboxamides using oxone as terminal oxidant.

Hofmann rearrangement of carboxamides to carbamates using Oxone as an oxidant can be efficiently catalyzed by iodobenzene. This reaction involves hypervalent iodine species generated in situ from catalytic amount of PhI and Oxone in the presence of 1,1,1,3,3,3-hexafluoroisopropanol (HFIP) in aqueous methanol solutions. Under these conditions, Hofmann rearrangement of various carboxamides affords corresponding carbamates in high yields.