Benzyl Bromide → 5(S)-[1(S)-(Boc-Amino)-2-(p-methoxyphenyl)ethyl]-3(R)-(phenylmethyl)dihydrofuran-2-(3H)-one

Participants

Reaction Steps

In analogy with Example 5d), 4.17 g (12.44 mmol) of 5(S)-[1(S)-(Boc-amino)-2-(p-methoxyphenyl)ethyl]dihydrofuran-2-(3H)-one, dissolved in 22.4 ml of THF and 2.5 ml of DMPU, are deprotonated, at -70° C., with 24 ml of a 1M solution of lithium bis(trimethylsilyl)amide in THF, and alkylated (-75° C., 1 h) with 1.5 ml (12.44 mmol) of benzyl bromide. Protonation, at -75° C., with 4.6 ml of propionic acid and 4.6 ml of water, extraction and column chromatography (SiO2, methylene chloride/ether 25:1) yields the title compound: TLC Rf (C)=0,74; tRet (II)=16.6 min; FAB-MS (M+H)+ =426.

Provenance & Evidence