Alkylation of furan, thiophene, and pyrrole with furfuryl alcohol in the presence of the strongly acidic Amberlyst 15 sulfo cation-exchange resin

✍ Scribed by I. G. Iovel'; Yu. Sh. Gol'dberg; M. V. Shimanskaya

• Publisher: Springer US
• Year: 1989
• Tongue: English
• Weight: 342 KB
• Volume: 25
• Category: Article
• ISSN: 0009-3122
• DOI: 10.1007/bf00470016

✦ Synopsis

The corresponding 2-furylhetarylmethanes were obtained by the reaction of furan, thiophene, or pyrrole with furfuryl alcohol in the presence of the strongly acidic Amberlyst 15 cation-exchange resin in the H + form. The alkylation of furan and thiophene takes place regiospecifically in the 2position, whereas 2-furyl-2-pyrrolyl-and 2-furyl-3-pyrrolylmethane in a ratio of 6.2:1 are formed in the case of pyrrole.

In an investigation of the hydroxymethylation of furan and silvan (~-methylfuran) in the presence of acidic catalysts (various cation-exchange resins in the H + form) [i] it was observed that weakly acidic (Amberlite IRC-50 with a carboxy function) and strongly acidic (Amberlyst 15 and Dowex 50W • 4 with an SO3H function) cation-exchange resins protonate formaldehyde and catalyze the formation of the corresponding alcohols; in addition, strongly acidic cation-exchange resins (in contrast to the weakly acidic resin) protonate the furylcarbinols formed, as a result of which the hydroxymethylation products are converted to di(2-furyl)-methanes: