7,7-dimethyl-1,4-dioxaspiro[4.5]decan-8-ol

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A solution of 7,7-dimethyl-1,4-dioxaspiro[4.5]decan-8-ol (1.0 equiv.) in 2.0 N hydrochloric acid aqueous solution (3.7 equiv.) and MeOH (0.9 M) was stirred at room temperature overnight. TLC (petroleum ether:ethyl acetate=3:1) showed that the reaction was completed. The solvent was removed under reduced pressure, the resulting residue was basified with saturated aqueous sodium bicarbonate solution and the aqueous layer was extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate and filtered. The filtrate was concentrated under vacuum to give 4-hydroxy-3,3-dimethylcyclohexanone (88% yield), which was used in the next step without further purification. 1H NMR (400 MHz, CDCl3) δ (ppm) 3.69-3.71 (m, 1H), 2.42-2.45 (m, 2H), 2.09-2.25 (m, 1H), 2.04-2.08 (m, 4H), 1.91-1.95 (m, 1H), 0.98 (s, 6H) The solvent was removed under reduced pressure the aqueous layer was extracted with ethyl acetate The combined organic layers were washed with brine dried over anhydrous sodium sulfate filtered The filtrate was concentrated under vacuum

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of 7,7-dimethyl-1,4-dioxaspiro[4.5]decan-8-one (1.0 equiv.) in MeOH (0.5 M) was added sodium borohydride (1.0 equiv.) slowly at 0° C. under nitrogen, and the resulting reaction mixture was stirred at room temperature for 60 min. TLC (petroleum ether:ethyl acetate=10:1) showed that the reaction was completed. Water was added, and the solvent was removed under reduced pressure. The aqueous layer was extracted with DCM. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate and filtered. The filtrate was concentrated under vacuum to give 7,7-dimethyl-1,4-dioxaspiro[4.5]decan-8-ol (99% yield), which was used in the next step without further purification. 1H NMR (400 MHz, CDCl3) δ (ppm) 3.85-3.94 (m, 4H), 3.37-3.40 (m, 1H), 1.41-1.81 (m, 7H), 0.97 (s, 6H). the resulting reaction mixture the solvent was removed under reduced pressure The aqueous layer was extracted with DCM The combined organic layers were washed with brine dried over anhydrous sodium sulfate filtered The filtrate was concentrated under vacuum