(R)-2-Methyl-CBS-oxazaborolidine → (S)-ethyl 2-(2-bromo-5-methyl-7-(trifluoromethylsulfonyloxy)benzo[d]thiazol-6-yl)-2-hydroxyacetate
Reaction equation
[Br:1][C:2]1[S:3][C:4]2[C:10]([O:11][S:12]([C:15]([F:18])([F:17])[F:16])(=[O:14])=[O:13])=[C:9]([C:19](=[O:25])[C:20]([O:22][CH2:23][CH3:24])=[O:21])[C:8]([CH3:26])=[CH:7][C:5]=2[N:6]=1.B1(C)OC(C2C=CC=CC=2)(C2C=CC=CC=2)[C@@H]2N1CCC2>C1(C)C=CC=CC=1>[Br:1][C:2]1[S:3][C:4]2[C:10]([O:11][S:12]([C:15]([F:18])([F:16])[F:17])(=[O:14])=[O:13])=[C:9]([C@H:19]([OH:25])[C:20]([O:22][CH2:23][CH3:24])=[O:21])[C:8]([CH3:26])=[CH:7][C:5]=2[N:6]=1Participants
4
Reactant 2
Product 1
Reagents, catalysts & solvents 1
Conditions
- Temperature
- -35 °C
Procedure
To a solution of 30 (8.30 g, 17.4 mmol) in toluene (70 mL) was added ((R)-2-methyl-CBS-oxazaborolidine (725 mg, 2.61 mmol). The reaction mixture was then cooled to −35° C. and a solution of catecholborane (freshly distilled) (1 M in toluene, 20.9 mL, 20.9 mmol) was added via addition funnel over 30 min. The reaction was stirred for 20 min while warming to −20° C. A 2 M solution of Na2CO3 was added (50 mL). The layers were separated, and the organic layer was washed with additional Na2CO3 solution (3×25 mL). The organic layer was dried, filtered, and concentrated in vacuo to give 31, which had analytical data to match 29. The compound was taken on to the next step without further purification.
Workup
- distillationa solution of catecholborane (freshly distilled) (1 M in toluene, 20.9 mL, 20.9 mmol)
- additionwas added via addition funnel over 30 min
- temperaturewhile warming to −20° C
- additionA 2 M solution of Na2CO3 was added (50 mL)
- customThe layers were separated
- washthe organic layer was washed with additional Na2CO3 solution (3×25 mL)
- customThe organic layer was dried
- filtrationfiltered
- concentrationconcentrated in vacuo
Sources & evidence
- ORD record
- ord-797163cf69cb4b53994386fc0bd948be
- Source dataset
- uspto-grants-2015_08
- Patent number
- US09096586B2
Reaction notes
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