Solvent-free microwave-assisted synthesis of β-keto esters

An efficient, scalable and sustainable approach for the microwave-assisted synthesis of β-keto esters is described. It is based on microwave activation of 2,2,6-trimethyl-4H-1,3-dioxin-4-one in the presence of an alcohol. This solvent- and catalyst-free methodology proved efficient with a range of alcohols regardless of their steric bulkiness and electronic nature. The method tolerates a range of substitution. It provides high yields and very low E-factors, acetone being the only byproduct. The products can generally be isolated by distillation or precipitation, overall offering a highly sustainable process.