Results The 1 equiv MCPBA oxidation of 18 was performed at-30" C in CDC13 under a nitrogen atmosphere for 1 h. The product mixture was filtered in an inert atmosphere at-45" C as quickly as possible in order to remove m-chlorobenzoic acid (MCBA). The'H NMR and 13C NMR spectra of the filtrate were recorded as soon as possible after filtration.
