[C:1](Cl)(=[O:5])[C:2](Cl)=O.[C:7]1([CH2:13][C:14]2[CH:22]=[CH:21][CH:20]=[CH:19][C:15]=2C(O)=O)[CH:12]=[CH:11][CH:10]=[CH:9][CH:8]=1.C[Li]>C(Cl)Cl.CCOCC>[C:7]1([CH2:13][C:14]2[CH:15]=[CH:19][CH:20]=[CH:21][C:22]=2[C:1](=[O:5])[CH3:2])[CH:12]=[CH:11][CH:10]=[CH:9][CH:8]=1Oxalyl chloride (4.1 ml, 47 mmol) was added to a solution of 2-(phenylmethyl)benzoic acid (from Aldrich) in methylene chloride (100 ml) over 5 minutes at room temperature. The solution was allowed to stir at room temperature for 2 hours. The solution was concentrated and the resultant orange gum azeotroped with benzene (twice) and placed under high Vacuum for 1 hour. In a separate flask, methyl lithium (1.4M in THF, 100 ml, 140 mmol) was added over 10 minutes to a slurry of CuI2 (13.432 gm, 42.3 mmole) in ether (125 ml). The slurry was allowed to stir for 2 minutes. The above-prepared acid chloride in ether (50 ml) at -78° C. was cannulated over 20 minutes into the dimethyl lithiumcuprate solution, which was also cooled to -78° C. The solution stirred for an additional 20 minutes, then was quenched with methanol (30 ml) and warmed to room temperature. The solution was then added to saturated NH4Cl (200 ml), and the aqueous layer was extracted with ether (twice). The organic layers were combined and washed with brine, then dried over MgSO4, filtered and concentrated to afford an orange oil. The crude oil was purified by flash chromatography on Merck silica gel in 5% EtOAc in hexane. The fractions containing the product were combined and concentrated to afford the title compound as a pale yellow solid (3.090 gm, 63%).
読み込み中…
