Methyl 5-(2-bromoacetyl)-2-(phenylmethoxy)benzoate → (R)-Methyl 2-(benzyloxy)-5-(2-bromo-1-hydroxyethyl)benzoate
Reaction equation
[CH3:1][O:2][C:3](=[O:22])[C:4]1[CH:9]=[C:8]([C:10](=[O:13])[CH2:11][Br:12])[CH:7]=[CH:6][C:5]=1[O:14][CH2:15][C:16]1[CH:21]=[CH:20][CH:19]=[CH:18][CH:17]=1>C1(C)C=CC=CC=1.O1CCCC1>[CH3:1][O:2][C:3](=[O:22])[C:4]1[CH:9]=[C:8]([C@@H:10]([OH:13])[CH2:11][Br:12])[CH:7]=[CH:6][C:5]=1[O:14][CH2:15][C:16]1[CH:17]=[CH:18][CH:19]=[CH:20][CH:21]=1Participants
4
Reactant 1
Product 1
Reagents, catalysts & solvents 2
Procedure
(R)-2-Methyl-CBS-oxazoborolidine (1.38 mL of a 1.0 M solution in toluene) was added to a solution of α-bromoketone 45 (5.00 g, 13.80 mmol) in tetrahydrofuran (80 mL). After stirring for 15 min, borane tetrahydrofuran complex (8.5 mL of a 1 M solution in tetrahydrofuran) was added dropwise over a 15 min period. After stirring at ambient temperature for 1.5 h, the reaction was quenched by the slow addition of methanol (8.5 mL). The solvent was removed under vacuum. The residue was taken up in a mixed solvent of hexanes and ethyl acetate (2:1). The solid was vacuum filtered through a pad of silica gel. Concentration of the filtrate and drying under vacuum gave 46 (4.86 g, 97%) as a white solid: 1H NMR (500 MHz, DMSO-d6) δ 3.32-3.58 (m, 1H), 3.64-3.68 (m, 1H), 3.81 (s, 3H), 4.78-4.80 (m, 1H), 5.21 (s, 2H), 5.83 (d, 1H), 7.22 (d, 1H), 7.31-7.33 (m, 1H), 7.38-7.49 (m, 5H), 7.61 (s, 1H).