A photoinduced, copper-catalyzed three-component radical cross-coupling of cycloketone oxime esters, alkenes, and terminal alkynes is described for the first time. Key to the success of this process was the integration of photoinduced iminyl radicalmediated C−C bond cleavage with the conceptual simplicity of copper-catalyzed radical cross-coupling. This protocol provides access to cyanoalkyl-containing propargylic compounds in good yields.
A photoredox-catalyzed iminyl radical-triggered C–C bond cleavage/addition/Kornblum oxidation cascade of cycloketone oxime esters and styrenes in DMSO is described for the first time.
On the basis of the strategy of iminyl radical-mediated C-C bond cleavage, a visible light photocatalytic radical addition/cyclization cascade is described, providing an efficient and regioselective access to cyanoalkylated 1,2,3,4-tetrahydrophenanthrenes.
In this report, we identify xanthate salts as a unique class of visiblelight-excitable alkyl radical precursors that act simultaneously as strong photoreductants and alkyl radical sources. Upon direct photoexcitation of xanthate anions, efficient deoxygenative alkenylation and alkylation of a wide range of primary, secondary, and tertiary alcohols have been achieved via a onepot protocol, avoiding any photocatalysts. This method exhibits a broad substrate scope and good functional group tolerance, enabling late-stage functionalization of complex molecules.
A light-driven, metal-free, and iminyl
radical-mediated ring-opening
C–C bond cleavage/addition cascade of O-4-methoxybenzyl
oxime ethers and alkenes is described for the first time. The reaction
shows a broad substrate scope and high functional group compatibility
with both components, giving the corresponding valuable oxo nitriles
in generally good yields. Key to the success of this protocol is the
generation of cyclic iminyl radicals from the O-4-methoxybenzyl
oxime ethers via a photocatalytic hydrogen atom transfer (HAT) process.
The proposed main pathway is also supported by the preliminary mechanistic
studies.
A copper-catalyzed regio-reversed asymmetric [3+2] cycloaddition of iminoesters with nitroolefins is disclosed for the first time. This method enables the facile synthesis of polysubstituted chiral pyrrolidines bearing at least one chiral quaternary center in high yields with excellent regio-, diastereo-, and enantioselectivity. The application of chiral P,S ligands and the unique effect of α-aryl groups on the iminoesters are key to the success of this method. The practicality and versatility of the reaction are also demonstrated.
An unprecedented dual photoredox/palladium-catalyzed iminyl-radical-mediated C–C bond cleavage and directed ortho C–H acylation of 2-arylpyridines by using oxime esters is described. Oxime esters can serve as efficient acyl sources through formation of the corresponding acyl radicals by photoredox-catalyzed iminyl-radical-mediated C–C bond cleavage. This redox-neutral protocol features excellent regioselectivity, a broad substrate scope, and good functional-group tolerance with respect to both components, giving a broad range of aryl ketones with generally good yields.
Ac opper-catalyzed regio-reversed asymmetric [3+ +2] cycloaddition of iminoesters with nitroolefins is disclosed for the first time.T his method enables the facile synthesis of polysubstituted chiral pyrrolidines bearing at least one chiral quaternary center in high yields with excellent regio-, diastereo-, and enantioselectivity.T he application of chiral P, Sligands and the unique effect of a-aryl groups on the iminoesters are key to the success of this method. The practicality and versatility of the reaction are also demonstrated.
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