Synthesis of γ-Lactams from Acrylamides by Single-Carbon Atom Doping Annulation

Carbon atom insertion into N-heterocyclic carbenes to yield 3,4-dihydroquinoxalin-2(1H)-ones

“…The structure of 4b was confirmed by X-ray analysis. Although the mechanism is currently not elucidated, the C13 (or C5a) of 4b is likely transferred from the C2 of the benzimidazolium (the carbene center), 12 indicating two molecules of each substrate are involved in the formation. It appears that the N -phenyl substituent changes the electronic properties of the desired quinoxalinone product, which leads to the occurrence of additional reactions.…”

Single‐Carbon Atom Doping Reactions Using Atomic Carbon and Its Equivalents

“…[33,34] Ylide 21 then undergoes nucleophilic attack to the ipso carbon of the aromatic ring on the nitrogen, which These types of SCAD reactions are also applicable to the corresponding α,β-unsaturated secondary amides (Scheme 10). [35] The overall transformation involves insertion of an carbon atom into CÀ H and NÀ H bonds without any rearrangement, which allows for the retrosynthetic simplicity [36] when applied to organic synthesis. A wide scope of substrates, such as cyclic or acyclic amides bearing an amine and an alkene, were compatible with this transformation.…”

Carbene-Stabilized Aluminacyclopropene–Cyclopropenylalane Rearrangement

“…Additionally, the C(4) atom adopts a triangular geometry with a total angle of 360.0°, and the C(4)–N(2) bond length of 1.297(3) Å aligns with a CN double bond, illustrating the imine feature of C(4)–N(2). Notably, the formation of 3 represents an exceptionally rare instance of a carbon atom extrusion reaction from an NHC …”

“…This principle has continued to inspire and shape the fields of organic and organometallic chemistry over the years . Recently, Tobisu and co-workers reported that N-heterocyclic carbenes (NHCs) could act as a carbon(0) source within the coordination sphere of a diimine ligand, facilitating the synthesis of γ-lactams through a novel single-carbon-atom doping annulation process . These findings raise a pertinent question: are the applications of carbon extrusion from NHCs limited solely to the observations made by Tobisu?…”