O1CCCC1.C1(C)C=CC=CC=1.[C:13]1([Mg]Br)[CH:18]=[CH:17][CH:16]=[CH:15][CH:14]=1.[CH3:21][C:22](=[O:26])[C:23](=[O:25])[CH3:24]>C1COCC1.C1(C)C=CC=CC=1>[OH:26][C:22]([C:13]1[CH:18]=[CH:17][CH:16]=[CH:15][CH:14]=1)([CH3:21])[C:23](=[O:25])[CH3:24]The process can also be run in mixtures of tetrahydrofuran and toluene, thereby making the process more economical. When 1.1 equivalent of phenylmagnesium bromide (1.9M in 50% THF/PhMe) was added to 2,3-butanedione in 50% THF/PhMe, crude product was isolated in 82.4% yield (Run 10, Table IV) after work-up. Short path vacuum distillation gave 3-hydroxy-3-phenylbutan-2-one in 68% yield. Alternatively, preparation of phenylmagnesium bromide in 38% THF/PhMe, followed by reaction with 2,3-butanedione in 38% THF/PhMe afforded 3-hydroxy-3-phenylbutan-2-one in 66.4% yield (Run 11, Table IV) after work-up and distillation. Similarly phenylmagnessium bromide in 25% THR/PheMe reacted with 2,3-butanedione in 25% THF/PheMe yielded 3-hydroxy-3-phenylbutan-2-one in 56.9% yield after work-up and distillation.
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