[OH:1][C@@H:2]1[CH2:6][CH2:5][O:4][C:3]1=[O:7].C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1.[Br:27][C:28]1[N:33]=[CH:32][C:31](O)=[CH:30][CH:29]=1>C1(C)C=CC=CC=1>[Br:27][C:28]1[N:33]=[CH:32][C:31]([O:1][C@H:2]2[CH2:6][CH2:5][O:4][C:3]2=[O:7])=[CH:30][CH:29]=1To a suspension of (R)-3-hydroxydihydrofuran-2(3H)-one (500 mg, 4.9 mmol) in toluene (15 mL) was added triphenylphosphine (1.54 g, 5.88 mmol) and 6-bromopyridin-3-ol (1.02 g, 5.88 mmol). The solution was cooled to 0° C. and degassed with nitrogen bubble for 10 minutes. Di-tert-butyl diazene-1,2-dicarboxylate was dissolved in toluene (5 mL) and added over a 5 minute period. The reaction was allowed to stir for 12 hours with warming to ambient temperature. The reaction was concentrated in vacuo and the resulting material purified by silica gel chromatography eluting 1:1 hexanes/EtOAc to yield (S)-3-(6-bromopyridin-3-yloxy)dihydrofuran-2(3H)-one (1.0 g, 79%) as an off white solid.
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