Synthesis of spiropyrans via Ru(II)-catalyzed coupling of 3-aryl-2 H-benzo[ b][1,4]oxazines with benzoquinones

Org Biomol Chem. 2024 Jan 31;22(5):998-1009. doi: 10.1039/d3ob01971c.

Abstract

An efficient Ru(II)-catalyzed C-H activation-based spiroannulation of benzoxazines with the easily available benzoquinone and N-sulfonyl quinone monoimine has been realized, providing a straightforward strategy to access NH-containing spiropyrans in moderate to good yields with good functional group compatibility. The procedure features atom- and step-economy, mild conditions, and excellent chemoselectivity. Moreover, a catalytically competent five-membered cycloruthenated complex has been isolated.