Chiral Quaternary Ammonium Aryloxide/N,O‐Bis(trimethyl‐ silyl)acetamide Combination as Efficient Organocatalytic System for the Direct Vinylogous Aldol Reaction of (5H)‐Furan‐2‐one Derivatives

A chiral quaternary ammonium amide was generated in situ from N,O‐bis(trimethylsilyl)acetamide (BSA) as non‐nucleophilic Brønsted base precursor and the combination of chiral quaternary ammonium halide/sodium aryloxide as chiral Lewis base. This system was applied to an anti‐selective organocatalytic direct vinylogous aldol (ODVA) reaction of (5H)‐furan‐2‐one derivatives with aldehydes. Several 5‐(1′‐hydroxy)‐γ‐butenolides were obtained in good diastereomeric ratios (up to 95/5) and excellent enantioselectivities (up to 94%) with both aliphatic or (hetero)aromatic aldehydes, so providing a rare example of general and efficient conditions for the ODVA reaction.