Cyclization of N-(3-Oxoalkyl)chloroacetamides Under Basic Conditions. Synthesis of cis-3,4-Epoxypiperidin-2-ones

It has been shown that N-(3-oxoalkyl)chloroacetamides (1) can be converted into cis-3,4-epoxypiridin-2-ones (2) upon treatment with t-BuOK in a t-BuOH-C6H6 solution due to a resulting intramolecular Darzens reaction. It has been found that under kinetically controlled reaction conditions (NaOH/C6H6), besides the intramolecular Darzens reaction an intramolecular alkylation takes place.