Photo-induced phosphorylation/cyclization of N-homoallyl and N-allyl aldehyde hydrazones to access phosphorylated tetrahydropyridazines and dihydropyrazoles

A photocatalytic radical carbophosphorylation/cyclization of N-homoallyl aldehyde hydrazones with phosphine oxides was developed under metal-free conditions, achieving phosphorylated tetrahydropyridazines in yields up to 95%. Phosphorylated dihydropyrazoles were also constructed, by reacting N-allyl aldehyde hydrazones with phosphine oxides under the same conditions.

Retracted Article: Molybdenum-silver co-catalyzed cycloaddition of alkynes with N-isocyanoiminotriphenylphosphorane (NIITP): an efficient strategy for the synthesis of monosubstituted pyrazoles

A highly efficient synthesis of monosubstituted pyrazoles from alkynes and N-isocyanoiminotriphenylphosphorane (NITTP) is developed via molybdenum-silver co-catalyzed [3+2] cycloaddition.

Zinc-promoted cyclization of tosylhydrazones and 2-(dimethylamino)malononitrile: an efficient strategy for the synthesis of substituted 1-tosyl-1H-pyrazoles

An efficient strategy for the synthesis of substituted 1-tosyl-1H-pyrazoles has been developed through a cyclization reaction of tosylhydrazones with 2-(dimethylamino)malononitrile.

Direct use of allylic alcohols for palladium-catalyzed synthesis of 3-allylbenzo[b]thiophenes, benzofurans and indoles in aqueous media

Palladium-catalyzed allylative cyclization of 1, 2 and 3 using simple allylic alcohols in aqueous media afforded 3-allylbenzo[b]thiophenes 4, 3-allylindoles 5 and 3-allylbenzofurans 6 in good yields.

Pd(ii)-catalyzed ligand controlled synthesis of pyrazole-4-carboxylates and benzo[b]thiophene-3-carboxylates

A simple change of the ligand and solvent allows controlled, effective switching between cyclization–carbonylation–cyclization-coupling (CCC-coupling) and cyclization–carbonylation reactions.

A novel methodology for synthesis of dihydropyrazole derivatives as potential anticancer agents

A flexible and efficient method for the synthesis of 4,5-dihydropyrazole derivatives has been developed.

Chemoselective synthesis of substituted pyrazoles through AgOTf-catalyzed cascade propargylic substitution-cyclization-aromatization

A cascade AgOTf-catalyzed chemoselective approach to 3,5/1,3-disubstitued pyrazoles from propargylic alcohols and para-tolylsulfonohydrazide has been developed. Good chemoselectivity is observed depending on the different substituents in the alkyne moiety of the propargylic alcohols, generating two different kinds of products through different aromatization mechanisms. The pyrazolo[5,1-a]isoquinoline skeleton can also be effectively constructed by this method through a cascade bicyclization process.