ChemInform Abstract: The Consequences of Strain Release in the Norbornyl Subunit of Isodicyclopentadiene on Cycloaddition Stereochemistry. Further Evidence That Orbital Tilting Serves as the Key Determinant of Contrasteric π-Facial Selectivity.

Abstract

Abstract Diels-Alder cycloadditions to 2 and 3 occur preferentially from the top face in contra-distinction to the behavior of isodicyclopentadiene (1). This reversal in facial stereoselectivity is shown not to arise from torsional constraints, but to be consistent with the overriding of steric effects by orbital tilting in 1.