The tricyclic α-keto hemiacetals 3a,b and 8a−d obtained from ruthenium-catalyzed oxidation oftetrahalonorbornyl derivatives possessing a pendant hydroxymethyl group were cleaved using Pb(OAc)4 or alkaline H2O2 to give γ-lactone-fused cyclopentane derivatives 5a,b and 9a−d. The α-ketohemiacetal 3b has also been elaborated to spiroepoxide derivative 25. The stable hydrate 4 formedfrom ruthenium-catalyzed oxidation of acrolein adduct 10 furnished an intramolecular hemiacetal11 upon cleavage with Pb(OAc)4. The α-halo ester moiety in 5a was transformed smoothly in ahighly regio- and stereoselective manner to α-hydroxy esters through a lactone-assisted intermediateto furnish 18.