Abstract
The stereochemistry of the thermal and catalytic ene reactions of methyl glyoxylate is examined. With ris-2-butene at 200 °C, a 54% yield of a 7.4:1 mixture of endo-exo adducts is obtained. With cyclohexene and ferric chloride catalyst, a 4.4:1 mixture of endo-exo adducts is obtained. Trisubstituted alkenes give very little selectivity. The intramolecular ene reaction of prenyl glyoxylate proceeds at 90 °C, giving a 1:1 mixture of cis- and irans-3-isopropenyl-2-hydroxybutyrolactones.