Ru(II)-catalyzed site-selective C5 acylmethylation/annulation of 2-arylquinolin-4(1H)-ones with sulfoxonium ylides via weak coordination.

Abstract

A novel ruthenium(II)-catalyzed, oxo-directed C5-H acylmethylation of 2-arylquinolin-4(1H)-ones with sulfoxonium ylides has been developed. Weak carbonyl coordination overrides the competing nitrogen center, providing excellent C5 selectivity. The procedure shows excellent tolerance of functional groups, a broad substrate range, and moderate to good yields. Subsequent Tf2O-mediated cyclization enables semi-one-pot access to fused pyrano[2,3,4-de]quinolones. Further authentication of the synthetic usefulness of the developed method comes from gram-scale synthesis and product derivatizations.