Synthesis
The general procedure for the synthesis of Fmoc-L-phenylalaninol from Fmoc-L-phenylalanine was as follows: Fmoc-L-phenylalanine (10 mmol) was dissolved in THF (10 mL) at 0 °C, followed by the sequential addition of DIPEA (11 mmol, 1.42 mL) and EtOAc solution of 50% T3P (20 mmol, 6.36 mL). The reaction mixture was stirred at this temperature for about 10 minutes. Next, aqueous NaBH4 solution (10 mmol, 388 mg, dissolved in 0.3 mL H2O) was slowly added to the reaction system at the same temperature. The reaction progress was monitored by TLC until the reaction was complete. After completion of the reaction, the solvent was removed by rotary evaporation and the crude product was extracted with EtOAc. The organic phase was washed sequentially with 5% citric acid solution (10 mL × 2), 5% Na2CO3 solution (10 mL × 2), water and saturated saline. Finally, the organic phase was dried over anhydrous Na2SO4 and concentrated under reduced pressure to obtain the target product Fmoc-L-phenylalaninol.
References
[1] Tetrahedron Letters, 2012, vol. 53, # 38, p. 5059 - 5063
[2] Journal of Organic Chemistry, 2001, vol. 66, # 25, p. 8454 - 8462
[3] Tetrahedron Letters, 2000, vol. 41, # 32, p. 6131 - 6135
[4] Organic Letters, 2008, vol. 10, # 10, p. 1881 - 1884
[5] Tetrahedron Letters, 1999, vol. 40, # 23, p. 4395 - 4396
