C[Si](C)(C)Cl.[CH3:6][O:7][C:8]1[CH:16]=[CH:15][CH:14]=[CH:13][C:9]=1[CH2:10][C:11]#[N:12].Br[CH:18]([CH3:24])[C:19]([O:21][CH2:22][CH3:23])=[O:20].[BH4-].[Na+].Cl>ClCCl.O1CCCC1.[Zn].C(O)C>[NH2:12][CH:11]([CH2:10][C:9]1[CH:13]=[CH:14][CH:15]=[CH:16][C:8]=1[O:7][CH3:6])[CH:18]([CH3:24])[C:19]([O:21][CH2:22][CH3:23])=[O:20]
150 g of zinc in 1.5 L of absolute dichloromethane are combined with 15 mL of trimethylchlorosilane under nitrogen and stirred for 30 minutes at ambient temperature. Then 900 mL of absolute tetrahydrofuran (THF) are added and heated to 42° C. To this is added dropwise a mixture of 147 g (1.0 mol) of 2-methoxybenzylcyanide 11 and 362 g (2,0 mol) of ethyl 2-bromopropionate in 100 mL of THF and the resulting mixture is then refluxed for a further 2 h. It is left to cool, decanted off from the excess zinc and after cooling to about 5° C. combined with 70 g (1.8 mol) of sodium borohydride. Then 250 mL of ethanol are added dropwise (development of gas). The mixture is left to react for 3 h at 5° C., 1 liter of 2 N hydrochloric acid is slowly added, the phases are separated and the aqueous phase is extracted twice with 200 mL of dichloromethane. The solvent of the combined organic phase is eliminated in vacuo, the residue is combined with ice and toluene and made alkaline with conc. ammonia. The phases are separated and the aqueous phase is extracted twice more with 800 mL of toluene. The combined organic phases are dried over magnesium sulfate, and the solvent is eliminated in vacuo. Yield 149 g (61%) oil.
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