Cycloaddition behavior of unsymmetric cyclopentadienone. Peri- and regio-selectivities
Abstract
An asymmetrically substituted cyclopentadienone, 2-methoxycarbonyl-5-methyl-3,4-diphenylcyclopentadienone 1a, was synthesized and cycloadditions of compound 1a with various unsaturated compounds involving conjugated medium-ring polyenes were investigated. The cycloaddition behavior was analyzed by frontier molecular orbital (FMO) theory, indicating that the reactivity, stereo- and regio-selectivities observed are entirely consistent with the FMO predictions.