反应详情

Analogously to Example 21 D) 1)c), 5.0 g (16.37 mmol) of 5(S)-[1(S)-(Boc-amino)-2-phenylethyl]-dihydrofuran-2-(3H)-one [Example 21 D) 1)b)] dissolved in 75 ml of THF are deprotonated at -75° C. with 32.7 ml of lithium bis(trimethylsilyl)amide 1M in THF and alkylated starting at -75° C. with 3.4 g (18.0 mmol) of 3-fluorobenzyl bromide (Fluka; Buchs/Switzerland) (warming up during 60 min up to max. -50° C.). Column chromatography (SiO2, hexane/ethyl acetate 3:1) yields the title compound: TLC Rf (D)=0.6; tRet (I)=17.2 min.

1. temperaturewarming up during 60 min up
2. custom-50° C.