Triethylamine → (S)-4-Benzyl-3-((2S,3R)-3-{4-[2-(2-tert-butyl-5-methyl-oxazol-4-yl)-ethoxy]-naphthalen-1-yl}-2-ethoxy-3-hydroxy-propionyl)-oxazolidin-2-one

Participants

Reaction Steps

0.234 g of (S)-4-benzyl-3-ethoxyacetyl-oxazolidin-2-one (0.889 mmol) was dissolved under an argon atmosphere in 3 ml of abs. CH2Cl2 and treated with 0.149 ml of triethylamine (1.2 eq.). After cooling to −78°, nBu2BOTf was added slowly (0.980 ml of 1M solution in CH2Cl2) and enolborinate formation allowed to proceed for 15 Min. at −78° and for 50 Min. at 0°. After recooling, a solution of 0.300 g of the above prepared 4-[2-(2-tert-butyl-5-methyl-oxazol-4-yl)-ethoxy]-naphthalene-1-carbaldehyde (0.889 mmol) in 5 ml of abs. CH2Cl2 was slowly added via dropping funnel and the mixture kept for 30 Min. at −78° and for additional 30 Min. at 0°. 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 (silica gel, hexane/AcOEt=1/1) left finally 0.268 g of the title compound as white foam.

Provenance & Evidence