ABSTRACT
A five-membered N-O heterocycle, 4,5-dihydro-1,2,4-oxadiazole, was found to act as a single nitrogen atom transfer reagent via elimination of a ketone/aldehyde and a nitrile. This reagent was successfully applied for the synthesis of isoxazoles from ynones promoted by Sc(OTf)3 or through Au(I)/Sc(OTf)3 synergistic catalysis. The efficiency of this protocol was also demonstrated by its application in modifications of structurally complex natural products and pharmaceuticals.
Subject(s)
Isoxazoles , Scandium , Nitrogen , Oxadiazoles , CatalysisABSTRACT
An efficient photoredox/nickel dual-catalyzed coupling of allyl trifluoroborates with aryl halides has been developed, which provides an attractive route to diverse-substituted allylic benzenes. The method offers several advantages, such as high efficiency and regioselectivity, mild reaction conditions, wide substrate scope, and functional group compatibility. Mechanistic studies suggest that a π-allyl nickel(III) intermediate generated via the addition of an allyl radical to nickel species is possibly formed as a key reaction intermediate.
ABSTRACT
A nickel-catalyzed highly regioselective addition/cyclization of ynamide-benzylnitriles with organoboronic acids has been developed. The reaction offers an attractive route for the construction of diamino-functionalized 1-arylnaphthalenes, which is difficult to synthesize by other methods. In addition, a wide range of functional groups are tolerated in this reaction.
ABSTRACT
Cyanation of unactivated primary and secondary alkyl mesylates with Zn(CN)2 catalyzed by nickel has been developed. The reaction provides an efficient route for the synthesis of alkyl nitriles with wide substrate scope, good functional group tolerance, and compatibility with heterocyclic compounds. Mechanistic studies indicate that alkyl iodide generated in situ serves as the reactive intermediate and the gradual release of alkyl iodide is crucial for the success of the reaction.
