The condensation of substituted o-methoxybenzaldehydes or o-hydroxybenzaldehydes with a resin-bound cyclic malonic ester 3 afforded the resin 4 without catalyst. Cyclisation of the resin 4 in sulfuric acid formed 3-carboxycoumarins in good yield and excellent purity.
Review on SPOS: (a). GuillierF., OrainD., and BradleyM., Chem. Rev., 2000, 100, 2091; (b). B. A. Lorsbach and M. J. Kurth. Chem. Rev., 1999, 99, 1541; (c) I. W. James. Tetrahedron, 1999, 55, 4855-4946.
2.
ArmstrongV., SotoO., ValderramaJ. A., and TapiaR.Synth. Commun., 1988, 18, 717
3.
(a) ChenB.C., HuangX., and WangJ., Synthesis, 1987, 482; (b) B. C. Chen, X. Huang and S. M. Ma, Synth. Commun., 1987, 17, 1519; (c) F. C. Ye, B. C. Chen and X. Huang, Synthesis, 1989, 4, 317; (d) X. Huang, B. C. Chen, G. Y. Wu and H. B. Chen, Synth. Commun., 1991, 21, 1213.
4.
(a) LiuZ.X., and HuangX., Tetrahedron. Lett., 2001, 42, 7655; (b) Z. X. Liu and X. Huang, J. Org. Chem. (In press).
5.
(a) McNabH., Chem. Soc. Rev., 1978, 7, 345; (b) B. C. Chen, Heterocycles, 1991, 32, 529.
6.
ClintonR.O., and LaskowskiS. C., J. Am. Chem. Soc., 1949, 71, 3602
7.
HogbergT., VoraM., DrakeS. D., MitschermL. A., and OhemD. T. W., Acta. Chem. Scand., B.1984, 38, 359
8.
LeonardoB., FilippoC., AnnaM. M., and DanielaS., J. Heterocy. Chem., 1995, 32, 573
