Rhodium(III)-Catalyzed Intramolecular Cyclization and Sequential Aromatization of Ynamides with Propargyl Esters: Access to 2,5-Dihydropyrroles and Pyrroles.

Disclosed herein is a rhodium(III)-catalyzed intramolecular cyclization of ynamides with propargyl esters. A variety of highly functionalized 2,5-dihydropyrroles were obtained in moderate to good yields with high E/Z selectivities. Subsequent oxidation of the products gave valuable pyrrole derivatives. Additionally, scale-up reactions and late-stage derivatizations highlight the potential synthetic utility of this methodology.

Cascade hydroarylation/Diels-Alder cycloaddition of alkynylindoles with electron-deficient alkynes and alkenes.

Herein, a novel cascade gold(I)-catalyzed hydroarylation of alkynylindoles and subsequent Diels-Alder cycloaddition with electron-deficient alkynes and alkenes is described. A variety of azepino-fused hydrocarbazoles and carbazoles were obtained in moderate to excellent yields. Key features of this methodology are low catalyst loadings, high regioselectivity, broad functional group tolerances, access to important heterocycles, and 100% atom economy.

Palladium(II)-Catalyzed Intramolecular [2 + 2 + 2] Annulation of Indolyl 1,3-Diynes: Construction of Azepino-Fused Carbazoles.

A novel palladium(II)-catalyzed intramolecular [2 + 2 + 2] annulation of indolyl 1,3-diynes is described in this contribution. A variety of azepino-fused carbazoles are obtained in moderate to excellent yields. The key to the success of this transformation is the use of a carboxylic acid as an additive. This protocol features broad functional group tolerances, easy handling in air, and 100% atom economy. Furthermore, scale-up reactions, late-stage derivatizations, and photophysical property investigations highlight the potential synthetic utility of this methodology.