A Facile Synthesis of Oxiranes Possessing Three or Four Carbonyl Groups

Tri-carbonylated oxiranes were efficiently synthesized by condensing a vicinal tricarbonyl compound with α-bromoketones in the presence of a base. This protocol was applicable to α–bromo-β-keto esters to create tetra-carbonylated oxiranes, from which trifunctionalized bromoalkene was competitively formed. The ratio of these compounds was influenced by the solvent and reaction temperature.