Nipate Dhananjay S, Swami Prakash N, Gadekar Amol B, Jangir Tarun, Rangan Krishnan, Kumar Anil
Department of Chemistry, Birla Institute of Technology and Science, Pilani, Pilani Campus, Pilani, Rajasthan, 333031, India.
Department of Chemistry, Birla Institute of Technology and Science, Pilani, Hyderabad Campus, Hyderabad, Telangana, 500078, India.
Chem Asian J. 2025 Feb 3;20(3):e202401104. doi: 10.1002/asia.202401104. Epub 2024 Dec 4.
A ruthenium(II)-catalyzed direct C-H/C-H (4+2) annulation of 2-aryl-N-heterocycles such as 2-aryl-4H-pyrido[1,2-a]pyrimidin-4-ones, 2-arylimidazo[1,2-a]pyridines, 2-aryl-2H-indazoles and 2-arylquinolin-4(1H)-ones with vinylene carbonate has been described. This one-pot cascade strategy provided the diversely substituted fused-polyheterocycles such as 7H-benzo[h]pyrido[2,1-b]quinazolin-7-ones, naphtho[1',2':4,5]imidazo[1,2-a]pyridines, indazolo[2,3-a]quinolines and benzo[c]acridin-7(12H)-ones in moderate to excellent yields. The developed protocol exhibited a broad substrate scope with good functional group tolerance and acid/base-free conditions. Based on a preliminary mechanistic investigation, a tentative mechanism of Ru(II)-catalyzed (4+2) annulation reaction has been proposed.
