A highly effective ligand-bound ruthenium catalyst for chemoselective degradation of aromatic rings to carboxylic acids

Abstract

A highly effective oxidation catalyst, generated in situ by reaction of cis-(2,2′-bipyridine)₂RuCl₂·2H₂O with sodium metaperiodate mimics ruthenium tetraoxide in the chemoselective degradation of aromatic rings in the 2-aryltricyclo[3.2.1.0^2,7]octan-6-ones (5a,b) and (6a,b) and the aryl substituted bicyclo[3.2.1]octanones (9a,b), (10a,b), (11), and (12) to the keto monocarboxylic acids (7a), (8a), (13a), (14a), (15a), and (16a) respectively. Similar oxidation reaction of the 2β-benzyl- and 2β-phenethyl-cyclohexane-1,3-carbolactones (17)–(20) affords the corresponding γ-lactone acids (20a)–(23a), whilst the fused tetracyclic hydroaromatic ketones (29a,b), (30a,b), (31a–c), and (35a,b) provide their respective keto dicarboxylic acids (32a)–(36a) in excellent yields. The incorporation of a methoxy substitution in the aromatic ring considerably facilitates the oxidation reaction.