Diisobutylaluminum hydride → Ammonium Hydroxide

Participants

Reaction Steps

To a solution of (±)-7-fluoro-2a-methyl-2a,5-dihydropyrrolo[4,3,2-de]quinoline-2,4(1H,3H)-dione from Step F (340 mg, 1.54 mmol) in THF (10 mL) at 0° C. was added DIBAL-H (7.72 mL of a 1 M solution in toluene, 7.72 mmol). The reaction mixture was stirred for 2 h and then quenched by the slow addition of saturated aqueous sodium potassium tartrate (100 mL) and extracted with EtOAc (3×50 mL). The combined organic extracts were washed with brine (20 mL), dried over Na2SO4, filtered, and concentrated in vacuo. The crude product was purified by silica gel chromatography, eluting with a gradient of CH2Cl2:MeOH:NH4OH—100:0:0 to 95:5:1, to give the racemic title compound. The enantiomers were resolved by HPLC, utilizing a ChiralPak AD column and eluting with MeOH. The first major peak to elute was 7-fluoro-2a-methyl-1,2,2a,5-tetrahydropyrrolo[4,3,2-de]quinolin-4(3H)-one, enantiomer A, the title compound, and the second major peak to elute was 7-fluoro-2a-methyl-1,2,2a,5-tetrahydropyrrolo[4,3,2-de]quinolin-4(3H)-one, enantiomer B. MS: m/z=207 (M+1).

Provenance & Evidence