C([Li])CCC.N12CCN(CC1)CC2.[Cl:14][C:15]1[CH:16]=[N:17][CH:18]=[C:19]([Cl:21])[CH:20]=1.CN(C)[CH:24]=[O:25]>C(OCC)C.O>[Cl:14][C:15]1[C:16]([CH:24]=[O:25])=[N:17][CH:18]=[C:19]([Cl:21])[CH:20]=1Add a solution of n-butyl lithium (37.5 mL, 0.06 mol, 1.6 M in hexanes) to a mixture of 1,4-diazabicyclo-[2.2.2]octane (6.16 g, 0.055 mol) in diethyl ether (250 mL) at −10 to −20° C. under a nitrogen atmosphere. Stir for 45 min. and then cool to −70° C. Add 3,5-dichloropyridine (7.40 g, 0.05 mol) in small portions and stir for 1.5 h at this temperature. Add N,N-dimethylformamide (7.75 mL, 0.10 mol) dropwise via syringe and stir for 2 h and allow to slowly warm to ˜−20° C. Add water (200 mL) is added and extract with ethyl acetate. Dry over sodium sulfate and concentrate in vacuo. Elute over silica gel with hexanes/ethyl acetate to give the desired aldehyde (2.12 g, 49%) as a light yellowish solid. MS(ES): (M+1)+ 174.8, 175.8 m/z.
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