Benzaldehyde → alpha-Vinylbenzyl alcohol

Beteiligte Stoffe

Reaktionsschritte

CuF2.2H2O (3 mg, 0.020 mmol) and (R)-DTBM-SEGPHOS (47 mg. 0.04 mmol) were added to methanol (0.7 mL) under an argon atmosphere, and the mixture was refluxed for 2 hours. Thereafter, the reaction mixture was allowed to stand for cooling to room temperature, and the volatile matter was removed in vacuo. Toluene (0.5 mL) was added to the resulting residue, and the operation for removal of the volatile matter was again carried out twice in vacuo (this catalyst preparation method is designated as “B”; hereinafter the same). The resulting CuF-phosphine complex was dissolved in DMF (1 mL), to which were then added benzaldehyde (67 μL, 0.67 mmol) and vinyltrimethoxysilane (206 μL, 1.34 mmol) at room temperature, and the mixture was stirred at 40° C. for 30 minutes. The reaction mixture was allowed to stand for cooling to room temperature, to which was then added tetrabutylammonium fluoride (TBAF) (1M/THF, 0.5 mL), and the mixture was stirred for 10 minutes. After adding water, the mixture was extracted with ethyl acetate, and the resulting organic layer was washed with saturated brine and then dried over anhydrous sodium sulfate. After drying, the solvent was distilled off, and the residue was subjected to silica gel column chromatography (ethyl acetate/hexane: 1/9 to 1/4), thereby obtaining desired 1-phenyl-2-propen-1-ol in a yield of 99%. Its optical purity was measured by HPLC and found to be 94% ee. Furthermore, its absolute configuration was determined in terms of an angle of rotation by comparison with an already reported value. As a result, the product was found to be an (S)-form.

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