C([Li])(C)(C)C.[CH3:6][O:7][C:8]1[CH:13]=[CH:12][CH:11]=[CH:10][C:9]=1[CH:14]1N(C)CCN1C.C([O:24][B:25](OC(C)C)[O:26]C(C)C)(C)C.Cl.C1C[O:38]CC1>C(OCC)(=O)C>[CH3:6][O:7][C:8]1[C:9]([CH:14]=[O:38])=[C:10]([B:25]([OH:26])[OH:24])[CH:11]=[CH:12][CH:13]=1
A solution of t-butyl lithium (9.0 mL, 1.7 M in pentane) was added to a stirred solution of 2-(2-methoxyphenyl)-1,3-dimethylimidazolidine (2.0 g, 9.8 mmol) in THF (5 mL) at −10° C. under N2 and stirred at 0-5° C. for 2 hours. The reaction mixture was cooled to −50° C. and triisopropylborate (3.5 mL, 15 mmol) was added. The solution was slowly warmed to 0° C. in 3 hrs. HCl (120 mL of 2N) was added at 0° C. and let it stirred for 30 min. The mixture was warmed to room temperature and was diluted with ethyl acetate. The organic layer was washed ( 2× HCl (1 N), brine), dried ( sodium sulfate) and concentrated to afford yellow crude product which purified by reverse phase HPLC chromatography. Upon removal of solvent 3-methoxy-2-formylphenylboronic acid crystallized as a light yellow solid, 1.3 g (yield 75%). ESI-MS m/e 177 (MH+).
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