Diisopropylamine → Lithium diisopropylamide

Participants

Reaction Steps

LDA-solution in THF was prepared according to standard procedure from 0.162 g of diisopropylamine (1.60 mmol) and 1.00 ml of 1.5 M nBuLi (hexane) in 3 ml of abs. THF at −10°. After cooling to −78°, 0.219 g of ethyl isopropoxyacetate (1.50 mmol), dissolved in 0.8 ml of THF, was added and stirring continued for 30 Min. to complete enolate formation. 0.169 g of the above prepared 4-[2-(2-cyclohexyl-5-methyl-oxazol-4-yl)-ethoxy]-3,5-dimethyl-benzaldehyde (0.495 mmol), dissolved in 2 ml of THF, was then added at −78° and the mixture kept for 10 Min. at this temperature. Pouring onto crashed ice/NH4Cl, twofold extraction with AcOEt, washing with water, drying over sodium sulfate, and evaporation of the solvents, followed by flash chromatography (SiO2, hexane/AcOEt=65/35) afforded 0.191 g of the title compound (syn/anti-isomers) as colorless, sticky oil.

Provenance & Evidence