methyl (2R)-2-[(2-methylpropan-2-yl)oxycarbonylamino]-3-phenylpropanoate

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a stirred solution of compound 31c (25.0 g, 90 mmol) in toluene-DCM (4:1, 1000 mL) was added dropwise a solution of DIBAL-H in toluene (1.0 M, 179 mL, 179 mmol) at −78° C. under argon and the mixture was stirred for 1 h at this temperature. Methanol (200 mL) was added immediately to quench the reaction. The reaction mixture was poured into a solution of 200 mL of 20% sodium potassium tartrate (Rochelle salt) and stirred at rt until the two layers separated. The organic layer was concentrated in vacuo and the residue was purified by CC (hexane/EA=2:1) to give compound 31d as a white solid (19.9 g, 89% yield). to quench the reaction stirred at rt until the two layers separated The organic layer was concentrated in vacuo the residue was purified by CC (hexane/EA=2:1)