B1(C)OC(C2C=CC=CC=2)(C2C=CC=CC=2)[C@H]2N1CCC2.B.C1COCC1.[Cl:28][CH2:29][C:30]([C:32]1[CH:41]=[C:40]([Cl:42])[C:35]2[NH:36][C:37](=[O:39])[O:38][C:34]=2[CH:33]=1)=[O:31]>C1COCC1>[Cl:28][CH2:29][C@H:30]([C:32]1[CH:41]=[C:40]([Cl:42])[C:35]2[NH:36][C:37](=[O:39])[O:38][C:34]=2[CH:33]=1)[OH:31]To a solution of (S)-Methyl-CBS-oxazaborolidine (1M in toluene, 0.745 mL, 0.745 mmol) and BH3-THF (8 mL, 8 mmol) is added at the same time a solution of BH3-THF (19 mL, 19 mmol) and a solution of the 6-Chloroacetyl-4-chloro-2-benzooxazolinone (37.98 mmol) in 19 mL of THF. Both solutions are added dropwise over 30 minutes. The solution is stirred for 1 hour and quenched with the slow addition of methanol (50 mL). The solution is concentrated and the residue chromatographed over a short silica gel column (1:1 hexane/ethyl acetate).
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