A two-step ball milling method synthesizes and purifies α,β-unsaturated esters

Over the last decade, solvent-free methods have been gaining interest as replacements for traditional organic chemistry techniques. While solvent-free methods are well known for many processes, a simple, solvent-free purification procedure that supplements them does not exist. We report the solvent-free synthesis of α,β-unsaturated esters using a solvent-free Horner–Wadsworth–Emmons (HWE) reaction using high-speed ball milling (HSBM). We were able to perform the HWE reaction on a variety of aldehydes, and isolate their respective a,b-unsaturated esters in high yields, purities, and diastereoselectivities.