Ethyl bromodifluoroacetate → Ethyl (3R,4S)-4-[[(1,1-dimethylethoxy)carbonyl]amino]-2,2-difluoro-3-hydroxy-6-methylheptanoate

Participants

Reaction Steps

1.45 g zinc powder are suspended in 30 ml tetrahydrofuran and heated to reflux temperature. 4.4 g ethylbromodifluoroacetate are added at once and as soon as a vigorous reaction is initiated 2 g of N--BOC--L--leucinal dissolved in 5 ml tetrahydrofuran are added dropwise. After 30 minutes the reaction mixture is allowed to cool, then taken up in ethyl acetate and washed with 2N tartaric acid. The organic phase is dried over magnesium sulfate, evaporated to dryness and chromatographed over silicagel using ether/hexane 2:8 as an eluent. N--BOC--(4S,3R)-2,2-difluorostatine ethyl ester is obtained ([α]D20 =-12.2°, c=0.29 in ethanol).

Provenance & Evidence