4,4-dimethylpent-2-enoic acid

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

Procedure: 4,4-Dimethyl-2-pentenoic acid (343 g), methanol/tetrahydrofuran=3/1 (150 mL) and ethanol (1240 mL) were mixed. After an addition of 10 w/w % palladium on activated carbon (31 g) to the mixture, the mixture was stirred at RT for 10.5 hr under hydrogen atmosphere (1 atm). The 10 w/w % palladium on activated carbon was filtered off and the filtrate was concentrated in vacuo to give the title compound (354 g) as a crude product. The 10 w/w % palladium on activated carbon was filtered off the filtrate was concentrated in vacuo

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

Procedure: To 20% sodium ethoxide in ethanol (1.02 L) was added ethyl diethylphosphonoacetate (516 mL) dropwise at ice temperature. After the mixture was stirred at ice temperature for 1.5 hr, a solution of 2,2-dimethylpropionaldehyde (260 mL) in tetrahydrofuran (510 mL) was added to the mixture at ice temperature. The mixture was stirred at RT for 3.5 hr and aqueous 4 N sodium hydroxide (885 mL) was added to the mixture at ice temperature. After the mixture was stirred overnight at RT, 6 N hydrochloric acid (802 mL) was added to the reaction mixture at ice temperature. The mixture was extracted with ethyl acetate (1 L), washed with water (1 L×5) and brine (500 mL), then dried over magnesium sulfate. The magnesium sulfate was filtered off and the filtrate was concentrated in vacuo to give the title compound (289 g) as a crude product. The mixture was stirred at RT for 3.5 hr After the mixture was stirred overnight at RT The mixture was extracted with ethyl acetate (1 L) washed with water (1 L×5) and brine (500 mL) dried over magnesium sulfate The magnesium sulfate was filtered off the filtrate was concentrated in vacuo