Mechanisms of Rh-Catalyzed Oxyaminofluorination and Oxyaminotrifluoromethylthiolation of Diazocarbonyl Compounds with Electrophilic Reagents.

Density functional theory calculations were performed to study the detailed reaction mechanisms of rhodium-catalyzed oxyaminofluorination and oxyaminotrifluoromethylthiolation of diazocarbonyl compounds with electrophilic N-F and N-SCF3-based reagents. The calculations show that the operating mechanisms for the two reactions are identical. The catalytic cycle starts with N2 dissociation to provide a rhodium-carbene intermediate, followed by nucleophilic attack of tetrahydrofuran on the carbene and a rhodium coordination change generating a rhodium-enolate intermediate. Subsequent electrophilic attack introduces the fluorine or the SCF3 moiety, and it is followed by nucleophilic attack of the remaining amino group to yield the final product.