Multicomponent Reactions of Phosphines, Diynedioates, and Aryl Aldehydes Generated Furans Appending Reactive Phosphorus Ylides through Cumulated Trienoates as Key Intermediates: A Phosphine alpha-Addition-delta-Evolvement of an Anion Pathway

Abstract

Multicomponent reactions of phosphines, diynedioates, and aryl aldehydes have been demonstrated, providing trisubstituted furans appending reactive phosphorus ylides, through cumulated trienoates as key intermediates. The proposed trienoate intermediates, 1,5-dipolar species formed via nucleophilic alpha-attack of phosphines toward diynedioates (alpha-addition-delta-evolvement of an anion, abbreviated alpha A delta E), undergo addition to aryl aldehydes followed by 5-endo-dig cyclization, proton transfer, and resonance to give trisubstituted furans. Furthermore, the phosphorus ylides are oxidized to alpha-keto ester furans and utilized as Wittig reagents.