Allyltributylstannane → (S)-alpha-[[(1,1-dimethylethoxy)carbonyl]amino]-4-(2-propenyl)benzenepropanoic acid methyl ester

Participants

Reaction Steps

Argon was passed through a solution of 7.0 g (0.0164 mol) of (S)-4-[[(trifluoromethyl)sulfonyl]oxy]-alpha-[[(1,1-dimethylethoxy)carbonyl]amino]benzenepropanoic acid methyl ester, 5.7 g (0.0165 mol) of allyltributyl tin, and 1.42 g (0.04 mol) of lithium chloride in 50 mL of dimethylformamide for 10 minutes and 210 mg (0.0003 mol) of bis(triphenylphosphine)palladium dichloride was added. The bath temperature was raised to 90°-95° C. for 40 minutes and the mixture was allowed to cool. The mixture was diluted with ether and washed with water and saturated sodium chloride solution and dried over magnesium sulfate. The residue obtained after filtration and evaporation was purified by preparative liquid chromatography using silica gel cartridges on a Waters Prep 500 chromatograph, eluting with 10% ethyl acetate-hexane to give 4.83 g (92%) of (S)-alpha-[[(1,1-dimethylethoxy)carbonyl]amino]-4-(2-propenyl)benzenepropanoic acid methyl ester, mp 56°-59° C.

Provenance & Evidence