Dichloromethane → cyclohexanecarboxylic acid tert-butyl ester

To a solution of cyclohexanecarboxylic acid (10.0 g, 78 mmol) in DCM (75 mL) concentrated sulfuric acid (765 mg, 7.8 mmol) was added. At a temperature between −15° C. and −10° C. isobutylene (10.94 g, 195 mmol) was introduced over 1 h. The cooling bath was removed and the reaction mixture was stirred at room temperature for 72 h. Then a second portion of isobutylene (10.94 g, 195 mmol) was introduced over 1 h at −10° C. The reaction mixture was stirred at room temperature for an additional 20 h, then NaHCO3 (7.864 g, 93.6 mmol) was added before the mixture was stirred at room temperature for another 1 h. Water (50 mL) was added under stirring. After 45 min the reaction mixture was worked up and washed until neutral. The organic phases were combined, dried over sodium sulfate and concentrated on a rotary evaporator. The crude product (13.5 g) was distilled over a Vigreux column at 35° C. (0.04 mbar) to afford 10.9 g (76%) cyclohexanecarboxylic acid tert-butyl ester as a colorless oil. 1H-NMR (CDCl3, 400 MHz): ppm 1.12-1.54 (m, 14H), 1.55-1.99 (m, 5H), 2.12-2.22 (m, 1H).

1. customThe cooling bath was removed
2. stirringThe reaction mixture was stirred at room temperature for an additional 20 h
3. stirringwas stirred at room temperature for another 1 h
4. stirringunder stirring
5. waitAfter 45 min the reaction mixture was worked up
6. washwashed until neutral
7. dry with materialdried over sodium sulfate
8. concentrationconcentrated on a rotary evaporator
9. distillationThe crude product (13.5 g) was distilled over a Vigreux column at 35° C. (0.04 mbar)

ORD record

ord-25cefb394efb45f381fc34f14784af8e

Source dataset

uspto-grants-2011_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08071803B2