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

Participants

Reaction Conditions

Reaction Steps

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).

Provenance & Evidence