An Ir(III)-catalyzed direct C-H amidation/cyclization of benzamides using 2,2,2-trichloroethoxycarbonyl azide (TrocN3) as the aminocarbonyl source is reported. With the aid of cesium carboxylate, the reactions proceed efficiently and with high regioselectivity, producing various functionalized quinazoline-2,4(1H,3H)-diones, which are important building blocks and key synthetic intermediates for biologically and medicinally important compounds. During the reactions, two new C-N bonds were formed by breaking C-H and N-H bonds sequence.

A low-temperature, protecting-group-free oxidation of 2-substituted anilines has been developed to generate an electrophilic N-aryl nitrenoid intermediate that can engage in C–NAr bond formation to construct functionalized N-heterocycles. The exposure of 2-substituted anilines to PIFA and trifluoroacetic acid or 10 mol % Sc­(OTf)3 triggers nitrenoid formation, followed by productive and selective C–NAr and C–C bond formation to yield spirocyclic- or bicyclic 3H-indoles or benzazepinones. Our experiments demonstrate the breadth of these oxidative processes, uncover underlying fundamental elements that control selectivity, and demonstrate how the distinct reactivity patterns embedded in N-aryl nitrenoid reactive intermediates can enable access to functionalized 3H-indoles or benzazepinones.

An I­(III)-catalyzed oxidative cyclization–migration tandem reaction using Selectfluor as the oxidant was developed that converts unactivated anilines into 3H-indoles is reported herein. The reaction requires as little as 1 mol % of the iodocatalyst and is mild, tolerating pyridine and thiophene functional groups, and the dependence of the diastereoselectivity of the process on the identity of the iodoarene or iodoalkane precatalyst suggests that the catalyst is present for the stereochemical determining C–N bond forming step.

Catalyst control of the site-selectivity of electron-rich alkyl, aryl disubstituted carbenes generated in situ from o-alkenyl-substituted N-tosylhydrazones was achieved in this study. Exposure of these substrates to copper iodide triggered the formation of α-alkoxy 2H-naphthalenones. This investigation established that changing the catalyst to a rhodium(II) carboxylate turned off cyclization and migration of the electron-rich metal carbene with the β-carboxylate and turned on allylic C-H bond functionalization to diastereoselectively afford 1H-indenes. Examination of the scope of this reaction revealed that ethereal, aminomethylene, and unactivated 2° C-H bonds could be functionalized.