A Novel Synthesis of Aminofurans Using a Four‐Component Reaction.

Abstract

Nucleophilic addition of triphenylphosphine to diesters (II) and subsequent protonation with aromatic carboxylic acids generates vinylphosphonium salts which rearrange and react with isonitriles to give fully substituted furans. -(ALIZADEH*, A.; ROSTAMNIA, S.; ZOREH, N.; OSKUEYAN, Q.; Synlett 2007, 10, 1610-1612; Dep. Chem., Univ. Tarbiat Modarres, Tehran, Iran; Eng.) -Mais 43-107

Unexpected isocyanide-based three-component bicyclization for the stereoselective synthesis of densely functionalized pyrano[3,4-c]pyrroles

“…Based on the experiment results and literature reports, 9,12 a reasonable mechanism for the present bicyclization reaction is described in Scheme 4. The zwitterionic intermediate A , generated by the addition of isocyanide 3 into dialkyl acetylenedicarboxylate 2 , reacts with 3-aroylacrylic acids 1 to yield 1,6-diene intermediate B , followed by Mumm rearrangement, 13 leading to intermediate C .…”

“…8 Of particular interest to us has been the exceptional reactivity of Huisgen 1,3-dipoles, generated in situ from the addition of isocyanide to electron-deficient alkynes, allowing the creation of complex and diverse drug-like small molecules. 9 For instance, Nair et al reported the [3+2] cycloaddition between activated styrenes and the zwitterion derived from isocyanide and dimethyl acetylenedicarboxylates (DMAD), furnishing substituted cyclopentadienes through a three-component reaction (Scheme 1a). 10 To continue this project and our isocyanide-enabled transformations, 11 we found that when activated styrenes employed in the above report were replaced by 3-aroylacrylic acids, the expected cyclopentadienes 5 were not observed (Scheme 1b).…”