This review covers recent developments of hypervalent iodine chemistry in dearomatizations, radicals, hypervalent iodine-guided electrophilic substitution, arylations, photoredox, and more.

All-electron numerical density functional theory calculations with scalar relativistic corrections have been utilized to examine the mechanism of the intramolecular rhodium-catalyzed hydroacylation reaction. The gas-phase results reveal a key branch point early in the reaction at the oxidative addition step wherein the two important pathways evolve through five-coordinate Rh(III) intermediates characterized by an apical acyl group and an equatorial hydride, orientations seemingly counter to trans influence arguments. These pathways account for the gross features of the experimental product distribution as well as the isotope labeling outcomes observed by previous investigators in this area. A greatly simplified approximation to modeling the reaction environment was applied that focused on redressing the coordinative unsaturation prevalent during certain steps of the catalytic process by including an explicit molecule of solvent or an additional molecule of substrate. Such an approach allowed us to explain the catalytic deactivation, substrate inhibition and dependence of the reaction rate on this coordinated ligand. Importantly, the application of a popular QM/MM method was unable to locate some of the key stationary points along the reaction path.

HIAT me, baby, one more time: Cyanocarbenes have been formed by the reaction of azides with hypervalent iodonium alkynyl triflates (HIATs). Experimental evidence supports the potential intermediacy of an azide‐substituted vinylidene or alkynyl azide, both of which could form a cyanocarbene. Trapping of the vinylidene and cyanocarbene includes OH insertion, dimethyl sulfoxide coordination, and cyclopropanation reactions.