Tetrahydrofuran → (3S,7aR)-6,6-Dibenzyl-3-tert-butyl-1,6,7,7a-tetrahydro-5-oxopyrrolo[1,2-c]oxazole-7a-carboxylic Acid Methyl Ester

Beteiligte Stoffe

Reaktionsschritte

To a solution of bicycle 17 (260 mg, 1.08 mmol) in THF (7.0 mL) under nitrogen were added at −78° C. successively a solution of LDA (1.5 M, 1.0 mL) and HMPA (1.0 mL). After 1 h, 4-bromo-1,1-diphenylbutane (360 mg, 1.25 mmol) in THF (3.0 mL) was added. After 6 h at −78° C., the reaction mixture was quenched with saturated NH4Cl solution. The product was extracted into EtOAc, and the combined organic layers were washed with brine, dried (Na2SO4), and concentrated under reduced pressure. Separation by column chromatography (SiO2, hexane/EtOAc 30:1) afforded starting material 17 (140 mg, 54% recovery) and compound 14g (70 mg, 31%) besides traces of 14h (2 mg) and 14i (2 mg).

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