Cp*Co(III)-Catalyzed C(8)-Nucleophilic Cascade Cyclization of Quinoline -Oxide with 1,6-Enyne.

The C(8)-selective nucleophilic cascade cyclization of quinoline -oxide with easily derived 1,6-enyne from phenol derivatives is demonstrated. A variety of quinoline -oxide and alkynes are discovered to be suitable for producing a library of quinoline -oxide tethered -hydrobenzofurans with high yields and excellent functional group tolerance. The utility of the protocol has been accomplished by post-synthetic modification of the cyclized product.

Room-temperature C-H bond alkynylation by merging cobalt and photocatalysts.

A new protocol is developed for the mono- and bis--C-H alkynylation of easily accessible benzamide derivatives using alkynyl bromides at room temperature by merging cobalt and photocatalysts. The diverse reactivity of various alkynyl bromides towards the C-H alkynylation and competing C-H/N-H bond annulation reactions has been demonstrated to give the corresponding products in good yields with excellent functional group tolerance.

Cp*Co-Catalyzed C(7)-H Bond Annulation of Indolines with Alkynes.

An efficient protocol for the synthesis of biologically essential pyrroloquinolinones has been developed under Cp*Co catalysis, which involves a cascade reaction of C(7)-H alkenylation with alkynes followed by nucleophilic addition. A wide variety of internal alkynes including enyne, diyne, and ynamide and more challenging terminal alkynes were successfully employed for the annulation in good to excellent yield with high regioselectivity.

Cross-Dehydrogenative Coupling/Annulation of Arene Carboxylic Acids and Alkenes in Water with Ruthenium(II) Catalyst and Air.

A cross-dehydrogenative coupling of arene carboxylic acids with olefins is reported with ruthenium(II) catalyst employing air and water as green oxidant and solvent, respectively. It offers a robust synthesis of valuable phthalide molecules. A one-pot sequential strategy is also disclosed to access Heck-type products that are apparently difficult to make directly from arene carboxylic acids.