Practical Synthesis of (E)‐α,β‐Unsaturated Esters from Aldehydes

Based on a modification of the Doebner–Knoevenagel reaction, a practical and highly efficient synthesis of α,β‐unsaturated esters with excellent regio‐ and stereoselectivity was developed. The reactions are catalyzed by 4‐dimethylaminopyridine in DMF at room temperature or below. Both aliphatic and aromatic aldehydes can readily be used in the process.