Catalysis of the knoevenagel condensation

✍ Scribed by Stéphane Chalais; Pierre Laszlo; Arthur Mathy

• Publisher: Elsevier Science
• Year: 1985
• Tongue: French
• Weight: 135 KB
• Volume: 26
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(00)88928-5

✦ Synopsis

Xonotlite alone or made more basic by doping of potassium t-butoxide catalyses the titleaction between aromatic aldehydes and malononitrile or alkyl cyanoacetates. At ambient temperatures, this procedure specifically gives high yields of F olefinic Knoevenagel products. INTEREST of preparative organic chemistry for the carbonyl group verges on prurience ! One of the first conversions of the carbonyl group into an olefin, dozens of years before the WittigI or the McMurry* routes, was devised by Knoevenage13. This reaction, now nearly a century-old, thus assumes continued importance. As part of a more general renovation program for important organic reactions 4-8 , we looked for a catalyst enabling Knoevenagel condensations to occur smoothly and quantitatively at room temperature. This is a reaction known to be catalysed by weak bases' under homogeneous conditions, and our recent successes with the Michael reaction8 under heterogeneous conditions, via a basic catalyst (xonotlite-t-butoxide) that we had devised, encouraged us to try homologous