N#N.ClCC1OC=[C:8]([C:10]([O:12]C)=O)N=1.[CH3:14][Mg]Cl.[NH4+:17].[Cl-:18].[CH2:19]1[CH2:23][O:22][CH2:21][CH2:20]1>>[Cl:18][CH2:19][C:23]1[O:22][CH:21]=[C:20]([C:10]([OH:12])([CH3:8])[CH3:14])[N:17]=1In a flame dried round-bottomed flask equipped with a magnetic stir bar and under inert atmosphere (N2), a solution of methyl 2-(chloromethyl)oxazole-4-carboxylate (Organic Process Research & Development 2001, 5, 37-44) (13.00 g, 74.04 mmol) in THF (433 mL) was treated dropwise at 0° C. with methylmagnesium chloride (51.8 mL of a 3.0 M solution in THF, 155.49 mmol) and the resulting orange solution was stirred for 1.5 h at 0° C. The reaction mixture was carefully poured over an ice-chilled sat. aq. NH4Cl solution (300 mL). It was extracted with EA (3×200 mL) and the combined org. layers were washed with brine (300 mL), dried over MgSO4, filtered and the solvent was removed under reduced pressure. Purification of the residue by FC (6:4 hept-EA) gave the title compound as a yellow oil: TLC: rf (6:4 hept-EA)=0.24. LC-MS-conditions 06: tR=0.49 min.
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