[H-].C([Al+]CC(C)C)C(C)C.CON(C)[C:14]([C:16]1[O:17][C:18]([Br:22])=[C:19]([Br:21])[CH:20]=1)=[O:15]>O1CCCC1>[Br:21][C:19]1[CH:20]=[C:16]([CH:14]=[O:15])[O:17][C:18]=1[Br:22]Diisobutylaluminum hydride (80 ml, 1M solution in toluene) was added to a solution of the product from Step 2 (20 g, 63.4 mmol) in tetrahydrofuran (160 ml) at −78° C. The mixture was stirred at −78° C. for 1.5 hours and was then quenched with a saturated aqueous solution of ammonium chloride (40 ml). The reaction was allowed to warm to room temperature, diluted with ethyl acetate and 5M hydrochloric acid (20 ml) and stirred for 30 minutes. The organic layer was separated, washed twice with water and then brine, dried and concentrated in vacuo to yield the title compound (12.9 g, 81%); 1H NMR (CDCl3) 9.52 (1H, s), 7.21 (1H, s).
Wird geladen…
