反应详情

温度

-60 °C

In analogy with Example 1h), 5.0 g (16.37 mmol) of 5(S)-[1(S)-(Boc-amino)-2-phenylethyl]dihydrofuran-2-(3H)-one [Example 2b)] dissolved in 100 ml of THF are deprotonated, at -75° C., with 32.7 ml of a 1M solution of lithium bis(trimethylsilyl)amide in THF, and alkylated with 2.51 ml (19.6 mmol) of 2,4-difluorobenzyl bromide (Aldrich; Milwaukee/U.S.A.) at -75° C. initially (heating to a maximum of -60° C. over a period of 2 h). Column chromatography (SiO2, hexane/ethyl acetate, 2:1) affords the title compound: TLC Rf (D)=0.5; tRet (II)=17.2 min.