Tributylphosphine → {(S)-6-[(R)-4-bromo-7-fluoro-indan-1-yloxy]-2,3-dihydro-benzofuran-3-yl}-acetic acid methyl ester

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Reaction Steps

A solution of di-tert-butyl azodicarboxylate (18.0 g) in tetrahydrofuran (80 mL) is added dropwise over 45 min to a solution of [(S)-6-hydroxy-2,3-dihydro-benzofuran-3-yl]-acetic acid methyl ester (11.0 g), (S)-4-bromo-7-fluoro-2,3-dihydro-1H-inden-1-ol (12.0 g) and tributylphosphine (19.3 mL) in tetrahydrofuran (320 mL) at −10° C. The resulting solution is stirred for 30 min and then poured into saturated aqueous NaHCO3 solution. The mixture is extracted with dichloromethane, and the combined organic phases are dried (MgSO4) and concentrated. The residue is chromatographed on silica gel (cyclohexane/ethyl acetate 90:10→70:30) to give the title compound. LC (method 1): tR=1.41 min; Mass spectrum (ESI+): m/z=421 [M+H]+.

Provenance & Evidence