Water → (R)-ethyl 3-cyclobutyl-3-(3-hydroxyphenyl)propanoate

Participants

Reaction Conditions

Reaction Steps

Methyl (3S)-3-cyclobutyl-3-(3-hydroxyphenyl)propanoate or methyl (3R)-3-cyclobutyl-3-(3-hydroxyphenyl)propanoate (70). A mixture of 3-hydroxyphenylboronic acid (available from Aldrich) (2.2 g, 16 mmol) and hydroxy[(S)-BINAP]-rhodium(I) dimer (0.24 g, 0.16 mmol) in 1,4-dioxane (10 mL, 3.2 mmol) was sparged with N2. To the mixture were added water (1.0 mL, 3.2 mmol) and (E)-ethyl 3-cyclobutylacrylate 70.C (0.56 mL, 3.2 mmol). The resulting red-brown solution was warmed to 45° C. and stirred for 3 hours (sealed vial). The mixture was cooled to room temperature, diluted with EtOAc, washed with saturated aqueous NaHCO3 and brine, dried (MgSO4), and concentrated. The crude product was purified by silica gel flash chromatography (0-25% EtOAc/hexane) to afford (S)-ethyl 3-cyclobutyl-3-(3-hydroxyphenyl)propanoate or (R)-ethyl 3-cyclobutyl-3-(3-hydroxyphenyl)propanoate 70 as a pale yellow oil (0.77 g, 96%) (92% e.e.). The enantiomerically enriched mixture was further purified by chiral HPLC (Chiralcel OD, 3% i-PrOH/hexane, 220 nm) to afford 70 as a colorless oil (>99% e.e.).

Provenance & Evidence