An iron-catalysed radical cyclization/C_(sp³)–H alkylation cascade between γ,δ-unsaturated oxime esters and glycine derivatives: access to pyrroline-containing amino acids

Abstract

An iron-catalysed selective C(sp3)‒H alkylation method for glycine derivatives is reported. Using γ,δ-Unsaturated oxime esters as both the alkylation reagent and terminal oxidant, N-aryl glycinates could be converted into a...

Cu-catalysed three-component C–H trifluoroalkylation of glycine derivatives: access to diverse CF3-containing amino acids

“…16 Our group has recently established a 3d metal-catalysed polar–radical crossover system promoted by N-based ligands. 17 This catalytic protocol enables the selective conversion of glycinates into highly active imine species, which effectively trap nucleophilic radicals, and may therefore provide a solution to the above-proposed trifluoroalkylation of glycine derivatives.…”

Cobalt(II)-Catalyzed Selective Three-Component Oxyalkylation of N-Aryl Glycinates: A Route to CF3-Labeled Threonine Analogues

“…Besides, a cyclization product 6aa was generated in the FeCl 2 -mediated case, possibly via a Povarov-type mechanism . In our previous research, improved reactivity and selectivity were achieved by combining a metal salt and a N-based ligand. , Unfortunately, both the established Cu and Fe recipe favored the oxytrifluoromethylation of silyl vinyl ether, resulting in 5a as the only product (entries 3, 4). Next, a few photoredox catalysts were inspected under blue light irradiation.…”

“…The research in our lab has been focused on 3d metal-catalyzed radical modifications of glycine derivatives. Iron and copper were proven highly effective in converting a N -aryl glycinate into a corresponding imine, which then serves an excellent alkyl radical acceptor to achieve an overall redox-neutral C sp 3 –C sp 3 bond formation. Based on this, we envisage to develop a three-component radical addition cascade with a glycinate, a protected enol, and a trifluoromethylating reagent, which would provide a novel approach to diverse CF 3 -containing threonine analogues (Scheme D).…”

Synthesis of multisubstituted carbazol-4-amines from tetrahydrocarbazol-4-one oximes

“…In the last decade, the generation of iminyl radicals from oximes and their derivatives has received sustained attention. 13 Iminyl radicals could be generated by transition-metal-catalyzed, 14 photo-, 15 and thermo-induced 16 N–O bond cleavages. They could undergo π-system addition, 17 ring opening, 13 b ,18 and hydrogen atom transfer (HAT) processes.…”