3,3-Diethoxypropyne → 5-(4,4-Diethoxy-1-(4-(tetrahydro-2H-pyran-2-yloxy)phenyl)but-2-ynyl)-2,2-dimethyl-1,3-dioxane-4,6-dione

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Reaction Steps

Propiolaldehyde diethyl acetal (5 g, 39 mmol) in anhydrous THF (65 mL) was cooled to −5° C. and treated with ethylmagnesium bromide (39 mmol in 14 mL of anhydrous THF) dropwise over 10 min. After 45 min., the solution of Grignard reagent was added to compound 52.1 in anhydrous THF (50 mL). After stirring 1 h, the reaction was quenched with saturated NH4Cl(aq) (20 mL) and diluted with hexanes (100 mL). After mixing vigorously, the layers were separated and the organic layer discarded. The aqueous layer was acidified and extracted twice with diethyl ether. The combined organic layers were washed with saturated brine, dried over Na2SO4, filtered, and concentrated under reduced pressure. The residue was used immediately without further purification. MS ESI (pos.) m/e: 478.3 (M+NH4)+.

Provenance & Evidence