Phase transfer catalysis by tetraethylammonium bromide: Nucleophilic opening of anhydrides using potassium superoxide in aprotic medium

Tetraethylammonium superoxide, generated in situ by the phase transfer reac tion of potassium superoxide and tetraethylammonium bromide, brings about a clean cleavage of various anhydrides, particularly those with high molecul ar weight in dry dimethylformamide. As an outcome, succinic anhydride 1; gl utaric anhydride 2; 3,3-dimethylglutaric anhydride 3; phthalic anhydride 4; diphenic anhydride 5; 1,2,3,4-tetrahydro-9-axo-1,4-ethanonaphthalene-2,3-e ndo-dicarboxyl anhydride 6; 1,4,5,6,7,7-hexachloro-5-norbornene-2,3-dicarbo xylic anhydride 7; endo-bicyclo [2.2.1] heptan-2-one-5,6-dicarboxylic anhyd ride 8; cis-5-norbomene-endo-2,3-dicarboxylic anhydride 9 and trans-1,2-cyc lohexane dicarboxylic anhydride 10 have been transformed into their corresp onding dicarboxylic acids in fairly good yields. The report demonstrates th e applicability of tetraethylammonium bromide as a phase transfer catalyst for efficient superoxide studies.