Diisopropylamine → Lithium diisopropylamide

Participants

Reaction Steps

LDA-solution in THF was prepared according to standard procedure from 0.180 g of diisopropylamine (1.783 mmol) and 1.080 ml of 1.5 M nBuLi (hexane) in 3 ml of abs. THF at −10°. After cooling to −75°, 0.214 g of ethyl ethoxyacetate (1.62 mmol), dissolved in 1.0 ml of THF, was added and stirring continued for 30 Min. to complete enolate formation. 0.178 g of the above prepared 4-(2-tert-butyl-5-methyl-oxazol-4-ylmethoxy)-benzo[b]thiophene-7-carbaldehyde (0.540 mmol), dissolved in 2.0 ml of THF, was then added at −75° and the mixture kept for another 30 Min. at this temperature. Pouring onto crashed ice/NH4Cl, twofold extraction with AcOEt, washing with water, drying over magnesium sulfate, and evaporation of the solvents, followed by flash chromatography (SiO2, hexane/AcOEt=7/3) afforded 0.201 g of the title compound (syn/anti-isomers) as yellowish oil.

Provenance & Evidence