Stereochemistry of Ene Reactions of Glyoxylate Esters

Abstract

The stereochemistry of the thermal and catalytic ene reactions of methyl glyoxylate is examined. With cis-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 frans-3-isopropenyl-2-hydroxybutyrolactones. © 1979, American Chemical Society. All rights reserved.