ABSTRACT The influence of 7-methoxy, p-toluene-sulfonyloxy, acetoxy, bromo, and chloro substitutents on the regiochemistry of oxygen insertion in the Baeyer-Villiger reaction of norbornan-2-ones 1a-j has been investigated. With meta-chloroperbenzoic acid 7-sys-substituted ketones 1a-c gave nearly 60:40 mixtures favoring bridgehead migrated lactones 2a-c, independent of the oxygen containing substituent; 7-syn-haloketones gave preferential methylene migrated lactones 3d-e. Except for the 7-anti-p-toluenesulfonyloxy ketone 1g, which gave a 60:40 mixture favoring bridgehead migrated lactones 2g, all other 7-anti-substituted ketones afforded solely bridgehead migrated lactones 2. Use of p-nitro-perbenzoic acid resulted in a slght increase in the preference for bridgehead migration with the 7-syn-substituted ketones 1a-c, while an increase in methylene migration was seen for haloketones 1d-e.
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