[C:1]1([Mg]Br)[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1.[CH:9](=[O:15])[CH2:10][CH2:11][CH2:12][CH:13]=[O:14].[Cl-].[NH4+]>CCOCC.O1CCCC1.O>[C:1]1([CH:13]2[O:14][CH:9]([OH:15])[CH2:10][CH2:11][CH2:12]2)[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1136.1 ml of a 3 M solution of phenyl magnesium bromide in ether was added, drop by drop, to a solution of 37.1 g of 4A in 375 ml of tetrahydrofuran at -60°±10° C. The mixture was allowed to warm (over a two-hour period) to room temperature. Then 75 ml of a saturated solution of ammonium chloride in water was added, the temperature of the mixture being held at 0°-5° C. The mixture was stirred for 15 minutes, then the supernatant oil was decanted, dried (MgSO4), and stripped of solvent. The residue was passed through a short column of silica gel using ethyl acetate as eluent. The eluate was stripped of solvent, and the residue was chromatographed (high pressure liquid) over silica gel, using as eluents one liter each, in sequence, of six mixtures of ethyl acetate and hexane, varying in content from 30% to 75% ethyl acetate, followed by two liters of ethyl acetate alone. Fractions 7 through 12 (in order of increasing polarity) were combined and stripped of solvent. The resulting solid was recrystallized from hexane to give tetrahydro-6-phenyl-2H-pyran-2-ol (as a mixture of diastereomers) (4B), as a solid, m.p.: 64.5°-71° C.
Wird geladen…
