B. V. Subba Reddy, S. Gopal Reddy, M. Durgaprasad, Manika Pal Bhadra and B. Sridhar
Org. Biomol. Chem., 2015,13, 8729-8733
DOI:
10.1039/C5OB01077B,
Paper
A wide array of aldehydes undergo smooth cross-coupling with 3-hydroxy-3-(4-hydroxybut-1-en-2-yl)-1-methylindolin-2-one in the presence of 10 mol% BF3·OEt2 at 0 °C in dichloromethane to afford the corresponding 2,3,5,6-tetrahydro-1′H-spiro[pyran-4,4′-quinoline]-2′,3′-dione derivatives in good yields with excellent diastereoselectivity. This is the first report on the synthesis of tetrahydro-1′H-spiro[pyran-4,4′-quinoline]-2′,3′-dione scaffolds through a cascade of Prins/pinacol reactions.