Diisobutylaluminum hydride → (7-Bromo-5-methyl-2,3-dihydrobenzo[b]oxepin-4-yl)methanol

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Reaction Steps

To a stirred solution of methyl 7-bromo-5-methyl-2,3-dihydrobenzo[b]oxepine-4-carboxylate from step H5 (2.0 g, 6.73 mmol), in THF (75 mL) was added DIBAL-H/THF (1.0 M, 67.3 mL, 67.3 mmol) at −60° C. The mixture was allowed to warm to rt over 3 h. The reaction was chilled to −78° C. and additional DIBAL-H in THF (5.0 equivalents) was added. The reaction was again allowed to warm to rt over 3 h. After an additional 20 h, the reaction mixture was carefully quenched with water. The aqueous mixture was extracted with diethyl ether. The organic layer was concentrated in vacuo. The residue was purified by silica-gel column chromatography (hexanes-50% EtOAc) to give (7-bromo-5-methyl-2,3-dihydrobenzo[b]oxepin-4-yl)methanol (1.53 g, 5.68 mmol, 84% yield). MS (M+H-water)+=251.

Provenance & Evidence