1-Heptyne → 1,1-Dimethoxynon-3-yne

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

1-Heptyne (50 ml, 381 mmole) is dissolved in 360 ml dry THF in a flame dried 2000 ml 3-neck round bottom flask under nitrogen. The solution is cooled to 0° C. and treated with n-butyllithium (232 ml, 360 mmole) dropwise over 40 minutes via a dropping funnel. The reaction mixture is stirred 30 minutes at 0° C., treated with hexamethylphosphoric triamide (68 ml, 391 mmole), and stirred an additional 30 minutes at 0° C. 1,1-Dimethoxy-2-bromoethane (43 ml, 364 mmole) is added dropwise to the reaction mixture over 10 minutes at 0° C. The reaction mixture is stirred 3 hours at 0° C. and an additional 72 hours at room temperature. The mixture is subsequently quenched with 5 ml water and the THF removed in vacuo. The amber oily residue is dissolved in 200 ml diethyl ether and poured into 100 ml 50% saturated sodium chloride. The aqueous layer is extracted with 3×75 ml diethyl ether. The organics are combined, washed with 6×50 ml 50% saturated sodium chloride, and dried over anhydrous magnesium sulfate. The diethyl ether is removed in vacuo and the red oily residue distilled under reduced pressure. After a 5 ml forerun, the fraction boiling at 65°-67° C. (0.5 mm) is collected to provide 42 g of the title compound as a colorless oil. Following the above procedure gives the title compound having the physical characteristic described below:

Herkunft & Nachweise