Binap, (A+-)- → 8-Bromo-3,4-dihydro-2H-1,4-benzoxazine

HRID 388289Notes

Reaction equation

C1(P(C2C=CC=CC=2)C2C=CC3C(=CC=CC=3)C=2C2C3C(=CC=CC=3)C=CC=2P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1.CC(C)([O-])C.[Na+].[Br:53][C:54]1[CH:63]=[CH:62][CH:61]=[C:60](Br)[C:55]=1[O:56][CH2:57][CH2:58][NH2:59]>C1(C)C=CC=CC=1.C(OCC)(=O)C.C1C=CC(/C=C/C(/C=C/C2C=CC=CC=2)=O)=CC=1.C1C=CC(/C=C/C(/C=C/C2C=CC=CC=2)=O)=CC=1.C1C=CC(/C=C/C(/C=C/C2C=CC=CC=2)=O)=CC=1.[Pd].[Pd]>[Br:53][C:54]1[C:55]2[O:56][CH2:57][CH2:58][NH:59][C:60]=2[CH:61]=[CH:62][CH:63]=1

Participants

Conditions

Temperature: 95 °C

Procedure

A three neck flask was charge with tris(dibenzylideneacetone)dipalladium(0) (0.37 g, 0.0004 mol, 2 mol % Pd), (±) racemic-2,2′-bis(diphenylphosphino)-1,1′-binaphthyl (0.64 g, 0.001 mol, 5 mol % Pd), and sodium tert-butoxide (2.7 g, 0.028 mol) and flushed with nitrogen. A solution of 2-(2,6-dibromo-phenoxy)ethylamine (6 g, 0.02 mol) in toluene (50 mL) was added. The mixture was heated to 95° C. and was stirred for 12 h. The mixture was cooled to room temperature, taken up in ethyl acetate, filtered and concentrated. The crude material was purified by flash chromatography on silica gel (eluting with hexane-ethyl acetate; 7:3, v/v) to give 8-bromo-3,4-dihydro-2H-benzo[1,4]oxazine as an oil (275 mg, 48%). The hydrochloride salt was prepared from ethanol-hydrogen chloride. MS: MH+=214. M.p. 184.1-195.4° C.

Workup

customflushed with nitrogen
temperatureThe mixture was cooled to room temperature
filtrationfiltered
concentrationconcentrated
customThe crude material was purified by flash chromatography on silica gel (
washeluting with hexane-ethyl acetate

Sources & evidence

ORD record: ord-ac46deb7121a448ba19a56a280184319
Source dataset: uspto-grants-2013_02
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08377931B2

Reaction notes

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