Enamine polymer-supported

Finally, the palladium-catalyzed cross-coupling reactions with supported enol phos-phonates were reported by Steel and coworkers (Table 1.13, Entry 1) Polymer-supported lactam enol phosphonates were prepared and multifunctional cleavage was demonstrated, using Suzuki conditions, to provide aryl enamines in good yields. 

Solid-phase synthesis of pyrido[2,3 pytirtiidines 514 was achieved by Hantzsch condensation of Wang resin-supported Knoevenagel derivative 513 with 6-aminouracil derivatives 512 as an a-oxo enamine component in the presence of ceric ammonium nitrate (CAN) in DMA followed by hydrolysis with TFA in CH2GI2. Compound 513 was prepared by treatment of a hydroxylated polymer, such as Wang or Sasrin resin, with diketene, followed by condensation with benzaldehyde (Equation 41) <1996TL4643>. 

A route taking advantage of the electrophilicity of the pyridyl N-oxide functionahty was reported by Smith et al. [386]. The authors used a polyacrylate polymer, which was terminally chlorinated with SOCI2 and then reacted with 2-chloropyridine N-oxide. The very unstable support-linked chloropyridinium species was claimed to react with the enamine. After acidolysis of the imine and basic hydrolysis of the N-oxyester, 2(6-chloro-2-pyridyl)cyclohexanone was obtained. 

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