Geometrically Specific Hydrogen Transfer in the Reaction of Terminally Alkyl-Substituted 1,3-Dienes with 1,4-Quinones

Abstract

Reaction of certain geometrically defined 1,1-dioxy-4-alkyl- and -4,4-dialkyl-substituted buta-1,3-dienes with halogenated quinones does not involve Diels–Alder or Michael addition chemistry. Instead, rapid competitive oxidation of the dienes to give 2,4-dienoate esters was observed. This new reaction involves strong spatial association between diene and quinone, hydrogen being transferred specifically from the (4E)-alkyl group. Its scope is compared with addition of the same terminally substituted dienes towards the reactive non-quinonoid dienophile tetracyanoethylene.