L-Phenylalanine → HCID 11306634, Verbindung

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

This product was obtained using the general procedure reported in the literature [(D. Seebach, E. Dziadulewicz, L. Behrendt, S. Cantoreggi, R. Fitzi, “Synthesis of Nonproteinogenic (R)- or (S)-Amino Acids Analogues of Phenylalanine, Isotopically Labelled and Cyclic Amino Acids from tert-Butyl 2-(tert-Butyl)-3-methyl-4-oxo-1-imidazolidinecarboxylate (Boc-BMI).” Liebigs Ann. Chem., pp 1215-1232 (1989)]. Diisopropylamine (0.9 mL, 6.4 mmol) dissolved in dry THF (5 mL) was cooled to −78° C. under argon and a solution of BuLi (2.5 M in hexane, 2.5 mL) was added drop wise. After 20 min of stirring at −78° C., a solution of (S)-tert-butyl-2-tert-butyl-3-methyl-4-oxoimidazolidine-1-carboxylate (3.0 g, 11.9 mmol) was added drop wise and the reaction mixture was stirred for 30 min at −40° C. A solution of 2-iodo-4-methoxybenzyl bromide (20) (2.08 g, 6.4 mmol) in dry THF (2 mL) was then added drop wise to the reaction mixture. The new reaction mixture was stirred for 2 hours at the same temperature and then poured into a saturated solution of NH4Cl. The product was extracted with EtOAc and the organic layer was washed with NaHCO3 solution followed by brine. The organic phase was dried over anhydrous Na2SO4, filtered and evaporated to produce a yellow oil. Flash chromatographic purification of the oily product provided pure (2S,5S)-tert-Butyl-5-(2′-iodo-4′-methoxybenzyl)-2-tert-butyl-3-methyl-4-oxoimida-zolidine-1-carboxylate (27) as a white solid (743.7 mg, 23%).

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