Synthese von 2‐Hydeoxy‐3‐methyl‐2‐hexen‐4‐olid

Synthesis of 2‐Hydroxy‐3‐methyl‐2‐hexen‐4‐olid The title compound 13a, a substance used in food‐flavoring, was synthesized in 89% overall yield, starting from methyl 2‐hydeoxy‐3‐butenoate (3 a ). The key step in this transformation is the isomerization of the CC bond in 3 a which yielded methyl 2‐oxobutanoate as an intermediate. The latter underwent a self‐condensation yielding 2‐hydroxy‐4‐(methoxycarbonyl)‐3‐methyl‐2‐hexen‐4‐olid ( 11 a ), which, after hydrolysis and decarboxylation, gave 13 a . In addition, the syntheses of five other compounds related to 13 a are reported.