含活潑亞甲基的酯（如丙二酸酯）在弱堿（胺、吡啶等）催化下加熱與醛或酮反應，形成縮合產物。后者經酯水解脫羧后得到α,β-不飽和酸。
反應機理
反應實例
用離子液體硝酸乙銨鹽為溶劑
參考文獻
1. Knoevenagel, E. Ber. 1894, 27, 2345-2346.
2. Knoevenagel, E. Ber. 1896, 29, 172-174.
3. Johnson, J. R. Org. React. 1942, 1, pp 210-265.
4. Jones, G. Org. React. 1967, 15, 204-599.
5. McNulty, J., Steere, J. A., Wolf, S. Tetrahedron Lett. 1998, 39, 8013-8016.
6. Betts, R. L., Diebes, A., Frenette, C. R., Langler, R. F. Sulfur Letters 1999, 23, 11-31.
7. Rodriguez, I., Sastre, G., Corma, A., Iborra, S. J. Catal. 1999, 183, 14-23.
8. Simpson, J., Rathbone, D. L., Billington, D. C. Tetrahedron Lett. 1999, 40, 7031-7033.
摘自：有機人名反應——機理及應用 第四版，Strategic Applications of Named Reactions in Organic Synthesis
