Boron trifluoride etherate → 1,1-Diethoxy-4,4-dimethoxypentan-3-one

Temperature

-78 °C

Boron trifluoride diethyl etherate (17.03 g, 120.0 mmol) was added dropwise over 15 min to a cooled (−40° C.) solution of triethyl orthoformate (14.82 g, 100.0 mmol) in dichloromethane (150 ml). Stirring was continued for 10 min then the solution was transferred to an ice-water bath and stirred at 0° C. for 20 min. The mixture was cooled to −78° C. and 3,3-dimethoxybutan-2-one (6.61 g, 50.0 mmol) was added followed by dropwise addition of N,N-diisopropylethylamine (19.39 g, 150.0 mmol) over 15 min. After stirring at −78° C. for 15 min the reaction was allowed to reach ambient temperature before pouring the resulting orange solution into a mixture of saturated sodium hydrogencarbonate solution (500 ml) and dichloromethane (200 ml). This mixture was vigorously stirred for 15 min, the organic phase was separated, washed with ice-cold 1M sulphuric acid solution (2×300 ml), ice-cold water (2×300 ml), dried over anhydrous magnesium sulfate and concentrated to give crude 1,1-diethoxy-4,4-dimethoxypentan-3-one (14 g, >100%) as an orange oil: δH (360 MHz, CDCl3) 1.18 (6H, t, J 7), 1.36 (3H, s), 2.93 (1H, d, J 6), 3.23 (3H, s), 3.25 (3H, s), 3.51-3.73 (4H, m), 5.03 (1H, t, J 6).

1. customthe solution was transferred to an ice-water bath
2. stirringstirred at 0° C. for 20 min
3. stirringAfter stirring at −78° C. for 15 min the reaction
4. customto reach ambient temperature
5. additionbefore pouring the resulting orange solution
6. stirringThis mixture was vigorously stirred for 15 min
7. customthe organic phase was separated
8. washwashed with ice-cold 1M sulphuric acid solution (2×300 ml), ice-cold water (2×300 ml)
9. dry with materialdried over anhydrous magnesium sulfate
10. concentrationconcentrated

ORD record

ord-6ddd65f874ef4690944173c9ea02d5fd

Source dataset

uspto-grants-2006_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07030128B2