Orbital distortion arising from remote substituents. Nitration, reduction, and epoxidation of fluorenes bearing a carbonyl or an olefin group in spiro geometry

Article abstract of DOI:10.1021/ja00049a012

Nitration of spiro[cyclopentane-1,9′-fluoren]-2-one with acetyl nitrate predominantly gave the 4-nitro derivative. In the reduction of substituted spiro[cyclopntane-1,9′-fluoren]-2-ones, the anti alcohols were favored in all cases. In the epoxidation of substituted spiro[cyclopent-2-ene-1,9′-fluorenes], the syn epoxides were favored. These distributions of the products can be interpreted in terms of orbital perturbations arising from interactions of the π orbitals of the aromatic and the carbonyl moieties or of the π orbitals of the aromatic and the olefin moieties, i.e., orbital mixing perturbation of the aromatic π orbitals through the π orbital of the bisected carbonyl (or olefin) group and the reciprocal perturbation of the π orbital of the carbonyl (or olefin) group arising from the orthogonal π aromatic orbitals.