EFFECT OF ALLYLIC SUBSTITUENTS ON THE FACE SELECTIVITY OF DIELS-ALDER REACTIONS OF SEMICYCLIC DIENES

Vinylcyclohexenes substituted allylically on the cyclohexene ring were examined as substrates in the Diels-Alder cycloaddition. In the octalin cycloaddition products, the relative stereochemistry of the one angular hydrogen relative to that of the allylic substituent was examined as a measure of the control of face selectivity by the substituent. In the 17 examples reported where the competition for control was between OH-H, MeO-H, (TMS)O-H, OH-CH3, OMe-CH3, and (TMS)O-CH3, the simplest rationale was that size alone controlled the face selectivity of the Diels-Alder cycloaddition. © 1990, American Chemical Society. All rights reserved.