Efficient oxidation-Wittig olefination-Diels–Alder multicomponent reactions of α-hydroxyketones

α-Hydroxyketones undergo efficient tandem oxidation-Wittig olefination reactions in the presence of an oxidant to produce high yields of γ-ketocrotonate products. On carrying out the oxidation-Wittig olefination reaction in the presence of 2,3-dimethyl-1,3-butadiene, a novel multicomponent reaction sequence provides access to cycloadducts in high yield.