Bromide ion → 5-[3-(Tert-butyl-dimethyl-silanyloxy)-phenyl]-5-oxo-pentanoic acid

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Reaction Steps

Magnesium (0.226 g, 8.58 mmol) was flame dried in a 50 mL RB flask equipped with addition funnel and magnetic stirrer under N2. When the flask had cooled, anhydrous THF (25 mL), a pinch of iodine, and a THF solution of Rieke magnesium (1 mL) were added, followed by a small portion of 3-bromophenoxy-tert-butyl(dimethyl)silane (2.24 g, 7.80 mmol) in THF (3 mL) with slight warming to initiate the reaction. The remainder of the bromide solution (10 mL) was added dropwise over 15 min. After 0.5 h this Grignard solution was added to a solution of glutaric anhydride (0.89 g, 7.8 mmol) in THF (10 mL) with cooling in an ice-H2O bath. After 2 h, the reaction mixture was diluted with EtOAc and washed with 1N NaOH (5×) to extract the product. The aqueous basic solution was cooled in an ice-H2O bath and acidified with 12N HCl, then extracted with CH2Cl2 (3×50 mL). The organic layers were combined, washed with brine, dried (MgSO4), filtered and concentrated to give the crude product. Purification on an ISCO Combiflash eluting with 3-7% MeOH/CH2Cl2 w/NH4OH gave the title compound. MS(M+1)323.

Provenance & Evidence