Rh(III)-Catalyzed Chemoselective [4 + 2] Annulations for the Synthesis of [1,3]Oxazinoindolones: A Combined Experimental and Computational Study.

The interaction of -alkoxy-1-indole-1-carboxamides with transition metals leads to indole-fused heterocyclic scaffolds through directing group leaving/migration, [3 + 2], N-C2 [4 + 1], and [4 + 2] annulations. However, the corresponding O-C2 [4 + 2] annulation reactions have never been reported. Herein, we report the chemoselective annulation of -alkoxy-1-indole-1-carboxamides catalyzed by Rh(III), affording [1,3]oxazinoindolones through a hitherto unknown reaction pathway.

Gold(I)-Catalyzed Regioselective Synthesis of Indenylidene Derivatives via 1,5-Acryl Migration.

A novel gold (I)-catalyzed synthetic strategy has been achieved for an efficient construction of indenylidene derivatives from substituted 1,6-diynes. This reaction describes the unique reactivity of gold catalysis in facilitating the intramolecular [3,3]-sigmatropic rearrangement, 5-exo dig cyclization followed by 1,5-migration of acryl group, resulting in the formation of substituted indenylidenes. Various substituted indenylidenes were successfully synthesized with up to 92 % yields.

Dual gold-catalyzed regioselective synthesis of benzofulvenes 5- cyclization.

An efficient dual gold-catalyzed regioselective synthesis of benzofulvenes has been developed from substituted allyloxy 1,5-diynes 5- cyclization. In this intramolecular organic transformation a new C-C bond formation occurs and moderate to very good yields are obtained in one pot.

Silver-catalyzed Regioselective Synthesis of N-aryl-1H-pyrazolyl-substituted Benzenesulfonamides from Ynamides and Pyrazoles.

Silver-catalyzed N-aryl-1H-pyrazolyl substituted benzenesulfonamide derivatives were obtained regioselectively from ynamides and pyrazoles. In this intermolecular organic transformation, several substituted benzenesulfonamides were obtained in good to excellent yields by forming a new C-N bond under mild reaction conditions.

Synthesis of Isoquinoline-Derived Diene Esters and Quinolin-2(1)-ylidene-Substituted 1,5-Diones from Enynones and (Iso) Quinoline -Oxides.

An efficient synthetic method was developed to access isoquinoline-derived diene esters from enynones and isoquinoline--oxides in an atom-economic manner. The isoquinoline-substituted diene esters were obtained in moderate to excellent yields via [3 + 2]-cycloaddition and isoxazole ring opening followed by a [1,5]-sigmatropic rearrangement reaction, which resulted in one C-C and two C-O bond formations. Further, quinolin-2(1)-ylidene-substituted 1,5-diones were achieved by reaction of enynones with quinoline--oxides in very good to high yields.