This study employed dual-functional Cu­(triNHC) (triNHC = tri-N-heterocyclic carbene) catalysts for the efficient coupling of CO2 with alcohols and amines to form various carbonates and carbamates with good yields. The direct synthesis of carbonates and carbamates from CO2 was realized by the Cu­(triNHC)-catalyzed carboxylative cyclization of CO2 and propargyl alcohol and subsequent reactions with an additional nucleophile (alcohols or amines). The free carbene dangled from the Cu­(triNHC) catalysts deprotonated the propargyl alcohol to increase the nucleophilicity toward CO2 and the subsequent cyclization was accelerated by the coordination of the copper ion of Cu­(triNHC). This dual function of Cu­(triNHC) is critical to the reaction of α-alkylidene carbonates with nucleophiles, forming carbonates or carbamates.

Mononuclear copper complexes modified with tridentate tris­(N-heterocyclic carbene) (triscarbene) ligands are synthesized. The structures of the copper–triscarbene complexes are characterized using X-ray crystallography, X-ray absorption near edge structure (XANES), and extended X-ray absorption fine structure (EXAFS) analyses. These copper–triscarbene complexes are utilized for the cycloaddition of alkynes and azides, and kinetic study results are presented.

Synthetic methods for constructing enantioenriched β-lactams are highly valuable given the ubiquity of this privileged heterocyclic unit in bioactive compounds, most notably in antibiotics such as penicillins and carbapenems. Intramolecular hydroamidation of β,γ-unsaturated amides would provide a convenient means to reach this alluring chemical space, yet it remains limited due to the regioselectivity issue arising from the difficulty associated with the formation of strained four-membered rings. Here we describe a NiH-catalysed strategy that addresses this challenge through the use of readily accessible alkenyl dioxazolone derivatives. The reaction transcends the conventional NiH operation mode via an unprecedented mechanism initiated by N-activation, thus allowing for proximal C–N bond formation with excellent regioselectivity, regardless of the electronic properties of substituents. This mechanistic platform is also highly effective for the enantioselective intramolecular hydroamidation of alkenes, which represents the first example of such a type of processes that enables the access to enantioenriched β-lactams.