Gold-Catalyzed Hydrohydrazidation of Terminal Alkynes.

Facile gold-catalyzed hydrohydrazidation of alkynes with various hydrazides RCONHNH (R = Alk or Ar; including those with an additional nucleophilic moiety) in the presence of PhPAuNTf (6 mol %) leading to a wide range of substituted keto- N-acylhydrazones (18 examples) in excellent to good yields (99-66%) is reported. This novel metal-catalyzed coupling proceeds under mild conditions (chlorobenzene, 60 °C), exhibits high functional group tolerance, and is insensitive to the electronic and steric effects of the substituents in the reactants.

Synthesis of benzannelated sultams by intramolecular Pd-catalyzed arylation of tertiary sulfonamides.

A new and efficient approach to five- and six-membered benzannelated sultams by intramolecular -arylation of tertiary 1-(methoxycarbonyl)methanesulfonamides under palladium catalysis is described. In case of the α-toluenesulfonamide derivative, an unexpected formation of a 2,3-diarylindole was observed under the same conditions.

Facile Gold-Catalyzed Heterocyclization of Terminal Alkynes and Cyanamides Leading to Substituted 2-Amino-1,3-Oxazoles.

Facile gold-catalyzed heterocyclization based upon intermolecular trapping of the generated α-oxo gold carbenes with various cyanamides R(2)R(3)NCN (R(2)/R(3) = Alk/Alk, -(CH2)2O(CH2)2-, Ar/Ar, Ar/H) has been developed. In most cases, 2-amino-1,3-oxazoles functionalized at the nitrogen atom as well as at the fifth position of the heterocyclic ring (12 examples) were isolated in good to moderate yields.