Synthesis
To a solution of the bis-phosphoramide catalyst (59 mg, 0.1 mmol) in CH2Cl2 (1 mL) and diisopropylethylamine (1.0 mL) under N2 at −78 °C was added allyltrichlorosilane (580 µL, 4.0 mmol). The solution was stirred at −78 °C for 10 min before benzaldehyde (200 mL, 2.0 mmol) was added. The resulting mixture was stirred at this temperature for 8 h whereupon the cold solution was poured in to a mixture of saturated aqueous NaHCO3 (10 mL) and saturated aqueous KF (10 mL) at 0 °C with vigorous stirring. The mixture was stirred for 2 h at room temperature and then fifiltered through Celite. The layers were then separated and the aqueous layer was extracted with CH2Cl2 (3 × 30 mL). The combined organic extracts were dried (MgSO4), fifiltered, and concentrated. The oily residue was purifified by column chromatography (silica gel) eluting with CH2Cl2:pentane (3:1) followed by CH2Cl2 to give 254 mg (85%) of the benzylic alcohol in 87% ee. Reference: Denmark, S. E.; Fu, J. J. Am. Chem. Soc. 2001, 123, 9488−9489
