Comprehensive Theoretical Study of Cp*Ir^III-Catalyzed Intermolecular Enantioselective Allylic C–H Amidation: Reaction Mechanism, Electronic Processes, and Regioselectivity

Abstract

Density functional theory was used to elucidate the reaction mechanism of Cp*IrIII-catalyzed intermolecular regioselective C(sp3)–H amidation of alkenes with methyl dioxazolones. All substrates, intermediates, and transition states were fully optimized at the ωB97XD/6-31G(d,p) level (LANL2DZ(f) for Ir). The computational results revealed that this amidation occurred through the IrIII/IrV catalytic cycle, involving four important elementary steps: C–H bond activation, oxidative addition of methyl dioxazolone, reductive elimination, and proto-demetalation, and the first was the rate-determining step. The C–H bond activation showed good α- and branch-regioselectivity, decided by the distortion energy of 2-pentene and the interaction energy of the transition state, respectively. The oxidative addition of dioxazolone occurred in one elementary step with CO2 disassociation. The reductive elimination showed good branch-regioselectivity determined by the distorted energy of the allyl group. In the proto-demetalation, hydrogen directly transferred from the oxygen atom to the nitrogen atom. Moreover, to clarify the effect of the substituted groups, selected 12 substrates were also discussed in this text.

Photocatalysed C–H amidation of indoles enabled by tert-butyl alkyl((perfluoropyridin-4-yl)oxy)carbamate

“…Traditional C–H amination/amidation of indoles heavily relied on transition-metal-catalysed protocols under harsh conditions with limited functional tolerance. 5 Compared with these classical strategies, photocatalysis opens up new vistas for the development of LSF pathways under mild conditions. 6 During the past few years, a series of N-centered radical (NCR) precursors have been identified for photo-induced amination/amidation.…”