SYNTHESIS OF MEDIUM-SIZED BICYCLIC COMPOUNDS BY INTRAMOLECULAR CYCLIZATION OF CYCLIC BETA-KETO RADICALS GENERATED FROM CYCLOPROPANOLS USING MANGANESE(III) TRIS(2-PYRIDINECARBOXYLATE)

Bicyclic cyclopropanols having olefinic side chain are oxidized with Mn(pic)3 to generate cyclic beta-keto radicals with ring-expansion, which cyclize intramolecularly affording bicyclic radical intermediates. The cyclized radicals are trapped with various radical-trapping reagents such as electron-rich or -deficient olefins, tributyltin hydride and diphenyl diselenide to give the corresponding functionalized products.