Gold-Catalyzed Heteroannulation of Anthranilic Acids with Alkynes: Synthesis of 3,1-Benzoxazin-4-ones.

We demonstrated a rapid and facile approach for the synthesis of various 3,1-benzoxazin-4-ones via a gold-catalyzed heteroannulation of readily available nonprotected anthranilic acids and simple aryl alkynes. Our preliminary mechanistic investigation indicated that the double incorporation of alkynes into anthranilic acids occurs through the formation of bisenamine intermediates.

Palladium-Catalyzed Heteroannulation of Salicylamides with Propargyl Carbonates: Synthesis of 1,4-Benzoxazepin-5-ones.

Herein, we report a palladium-catalyzed method to synthesize 1,4-benzoxazepin-5-ones using salicylamides and propargyl carbonates. The heteroannulation provides a wide range of products in good to excellent yields with broad functional group tolerance. In addition, HO is used as a low-cost, abundant, and safe solvent, which is important in terms of sustainability.

Chlorobenzene-driven palladium-catalysed lactonisation of benzoic acids.

Herein, we developed a palladium-catalysed C-H cyclisation of benzoic acids in chlorobenzene without additional oxidants. The key to the success of these reactions is the use of chlorobenzene, which serves a dual role as a solvent and an oxidant, thus providing a simple and efficient method for synthesising phthalides.

Rhodium-Catalyzed Cyclization of 2-Ethynylanilines in the Presence of Isocyanates: Approach toward Indole-3-carboxamides.

Catalytic synthesis of indole-3-carboxamides from 2-ethynylanilines and isocyanates was achieved in the presence of a rhodium catalyst through a tandem-type, cyclization-addition sequence. This tandem-type process can be performed under mild reaction conditions, affording 2,3-disubstituted indoles in a one-pot manner generally in good to excellent yields. The broad substrate scope and good functional group compatibility make the method highly efficient and widely applicable, providing a facile and entirely novel route toward variously substituted indole-3-carboxamides.