The general procedure for the synthesis of 6-(tert-butoxy)-6-oxohexanoic acid from the compound (CAS: 52221-08-6) was as follows: tert-butyl adipate (9.9 g, 45.8 mmol) was dissolved in a mixed solvent of ethanol (70 mL) and tetrahydrofuran (70 mL), and the reaction was carried out by slow addition of aqueous sodium hydroxide solution (1 N, 137 mL, 137 mmol) and the reaction was stirred for 2 hours. After completion of the reaction, the mixture was diluted with water and washed with dichloromethane (2 x 70 mL). Subsequently, the mixture was diluted with dichloromethane (100 mL) and acidified with aqueous hydrochloric acid (1 N, 150 mL) to pH ≈ 2. The organic layer was separated and the aqueous phase was further extracted with dichloromethane (2 × 50 mL). All organic layers were combined, dried with anhydrous magnesium sulfate, filtered and concentrated under reduced pressure to afford the title compound 6-(tert-butoxy)-6-oxohexanoic acid (7.82 g, 85% yield). The product was characterized by 1H NMR (C6D6, δ, ppm): 1.48 (9H, s, -OtBu), 1.52 (4H, m, -(CH2)2-), 2.05-2.10 (4H, m, 2*-CH2COO-).
