The Stereochemistry of Diels-Alder Adduct of 5-Methyl-2-cyclohexene-1-one with Butadiene

Abstract

The Diels-Alder reaction of 5-methyl-2-cyclohexene-1-one (I) with butadiene was examined. It was concluded that addition of butadiene to the dienophile (I) took place from the opposite side to a secondary methyl side to give initially the cis adduct (IIb), which then epimerizes mostly to the trans derivative (IIa).