“…Dimethyl d , l -2,3-Di- tert -butylsuccinate ( dl -10). 13b Dione 1g (52.0 mg, 0.268 mmol) in 0.5 mL of CDCl 3 and 50 μL of MeOH was irradiated for 12 h at 6 °C with 350 nm light. The solvent was evaporated, leaving d , l - 10 (69.2 mg, 0.268 mmol, 100%) as the sole product: 1 H NMR (CDCl 3 ) δ 1.02 (s, 18), 2.50 (s, 2), 3.63 (s, 6); 13 C NMR (CDCl 3 ) δ 28.0, 34.3, 51.1, 54.0, 174.2; IR (CDCl 3 ) 1733 (vs), 1721 (vs) cm -1 ; EIMS m/z 227 (M + − MeO, 14), 145 (90), 131 (58), 113 (65), 57 ( t -Bu + , 100).…”