Tributylphosphine → {(S)-6-[(R)-4-bromo-5-trifluoromethyl-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 (6.3 g) in tetrahydrofuran (20 mL) is added dropwise over 45 min to a solution of [(S)-6-hydroxy-2,3-dihydro-benzofuran-3-yl]-acetic acid methyl ester (4.71 g), (S)-4-bromo-5-trifluoromethyl-indan-1-ol (6.00 g), and tri-n-butyl-phosphine (6.9 mL) in tetrahydrofuran (50 mL) at −10° C. The resulting solution is stirred in the cooling bath for 2.5 h and then diluted with water. The resulting mixture is extracted with ethyl acetate. The combined extracts 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 2): tR=0.85 min; Mass spectrum (ESI+): m/z=471/473 (Br) [M+H]+.

Provenance & Evidence