Kinetic Separation and Asymmetric Reactions of Norcaradiene Cycloadducts: Facilitated Access via H₂O-Accelerated Cycloaddition

We exploit the Buchner reaction to access 1,2-disubstituted cyclohexadiene synthons (norcaradienes), which participate in H2O-accelerated cycloaddition with dieneophiles to provide cyclopropyl-fused [2.2.2]-bicyclooctene derivatives in good yields. Regioisomeric mixtures can be kinetically separated by exploiting different reaction rates in Diels-Alder reactions. Meso-Diels-Alder products may be enantioselectively desymmetrized, providing highly substituted cyclohexanes with up to seven contiguous stereocenters.