Cover Feature: Formal [2+2+1] Synthesis of Tetrasubstituted Furans from Aldehydes, Acetylenedicarboxylates, and Acyl Compounds (Eur. J. Org. Chem. 33/2019)

The Cover Feature shows the formal [2+2+1] synthesis of tetrasubstituted furans from aldehydes, acetylenedicarboxylates and acyl chlorides or trifluoroacetic anhydride using 4‐picoline and phosphines under the metal‐free and mild conditions. In the present method, 4‐picoline promotes the formation of α,β‐enone intermediates from aldehydes and acetylenedicarboxylates followed by the 1,4‐addition (O‐acylation) with acyl compounds and phosphines to give these furan products through an intramolecular Wittig reaction. More information can be found in the Full Paper by A. Saito et al.