6533b82afe1ef96bd128c24f
RESEARCH PRODUCT
NHC-Stabilized Gold(I) Complexes: Suitable Catalysts for 6-exo-dig Heterocyclization of 1-(o-Ethynylaryl)ureas
Mercedes Medio-simónCarmen Ramírez De ArellanoAna Belen CuencaGregorio AsensioAna Gimenosubject
chemistry.chemical_classificationLigandOrganic ChemistrySubstituentCationic polymerizationAlkyneRegioselectivityBiochemistryMedicinal chemistryCatalysisMetalchemistry.chemical_compoundchemistryvisual_artvisual_art.visual_art_mediumOrganic chemistryHydroaminationPhysical and Theoretical Chemistrydescription
3-Substituted 1-(o-ethynylaryl)ureas 1 selectively undergo either 6-exo-dig or 5-endo-dig cyclization (to give 4-methylene-3,4-quinazolin-2-ones 2 or indoles 3, respectively) depending on the choice of the metal, ligand, and reaction conditions. The best results (up to 96% yield) in the preparation of the hydroamination products 2 are achieved with the highly bulky NHC-stabilized cationic gold(I) complex [Au(IPr)](+). Conversely, ureas bearing an internal alkyne lead to the 5-endo-dig cyclization mode regardless of the gold(I) complex employed. Whereas the nature of the substituent at N-3 does not have any influence on the regiochemistry observed, it does, in some cases, affect the efficiency of these transformations.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2010-04-15 | Organic Letters |