[O:1]1[C:7]2[CH:8]=[CH:9][CH:10]=[CH:11][C:6]=2[N:5]([C:12]([O:14]C(C)(C)C)=O)[CH2:4][CH2:3][CH2:2]1.CN(C)[CH2:21][CH2:22][N:23]([CH3:25])[CH3:24].[CH:27]([Li])([CH2:29][CH3:30])[CH3:28].[CH3:32]N(C)C=O.[CH2:37](OCC)[CH3:38]>C1CCCCC1>[CH2:22]([N:23]1[CH2:25][C@H:38]2[C@H:37]([C:12](=[O:14])[N:5]3[CH2:4][CH2:3][CH2:2][O:1][C:7]4[CH:8]=[CH:9][CH:10]=[C:11]2[C:6]3=4)[CH2:24]1)[C:21]1[CH:32]=[CH:30][CH:29]=[CH:27][CH:28]=1To a solution of tert-butyl 3,4-dihydro-1,5-benzoxazepine-5(2H)-carboxylate (2.15 g, 8.62 mmol) in 50 mL of diethyl ether at −78° C. was added N,N,N′,N′-tetramethylethylenediamine (1.6 mL, 10.35 mmol) and then sec-butyllithium (8.0 mL of a 1.3 M solution in cyclohexane, 10.35 mmol) was added dropwise via addition funnel. The mixture was stirred at −78° C. for 1 h and then N,N-dimethylformamide (1.0 mL, 12.93 mmol) was added dropwise in 10 mL of diethyl ether and the resulting mixture was stirred at −78° C. for 1 h. The reaction was quenched by the addition of 10 mL of saturated aqueous ammonium chloride and then was diluted with water and ethyl acetate. The organics were washed with 10% aqueous HCl, sat'd aq. sodium bicarbonate and brine, dried (MgSO4) and concentrated in vacuo. The residue was purified by flash chromatography (elution with 5:1 hexane/ethyl acetate) to afford 2.0 g (84%) of the title compound as an oil which was determined to be a mixture of the title compound and the 9-formyl regioisomer. The mixture of products was carried forward.
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