Construction of Benzimidazolone Derivatives via Aryl Iodide Catalyzed Intramolecular Oxidative C-H Amination

Taming Tethered Nitreniums for Alkene Functionalization Reactions

We present the first examples of amino-trifluoroacetoxylations of alkenes using N-alkoxy carbamate tethers. Hypervalent iodine oxidants mediate this transformation, providing a "green" alternative to existing intramolecular amino-hydroxylation protocols which use toxic metals such as osmium. In all cases examined, the reaction is regioselective and stereospecific, with the geometry of the starting alkene controlling the diastereomeric outcome. By analogy to prior art and from our own observations, we posit that a transient nitrenium species serves as a key intermediate.

Intermolecular α-Functionalization of Benzylamides with N-Nucleophiles via Oxidative Umpolung: Synthesis of Tetrasubstituted 3,3'-Oxindoles

A hypervalent iodine-mediated intermolecular α-umpolung reaction between α-aryl- or alkyl-substituted amides and benzotriazoles or purine derivatives as N-centered nucleophiles has been established. The reaction involves sequential intra/intermolecular oxidative C-N couplings in a controlled manner, affording tetrasubstituted 3,3'-oxindoles in moderate to good yields. This approach efficiently addresses the challenges in constructing tetrasubstituted carbon centers via α-umpolung functionalizations of carbonyl compounds and serves as a new strategy for synthesizing biologically important 3,3'-disubstituted oxindoles.