Br[C:2]1[CH:7]=[C:6]([CH3:8])[N:5]=[C:4]([CH3:9])[CH:3]=1.C([Li])CCC.[CH2:15]([Sn:19](Cl)([CH2:24][CH2:25][CH2:26][CH3:27])[CH2:20][CH2:21][CH2:22][CH3:23])[CH2:16][CH2:17][CH3:18]>C(OCC)C>[CH3:8][C:6]1[CH:7]=[C:2]([Sn:19]([CH2:20][CH2:21][CH2:22][CH3:23])([CH2:24][CH2:25][CH2:26][CH3:27])[CH2:15][CH2:16][CH2:17][CH3:18])[CH:3]=[C:4]([CH3:9])[N:5]=1A 22 L flask was charged with 740 g of 4-bromo-2,6-lutidine and 10.0 L of diethyl ether and cooled to -60° C. in a Dry Ice/acetone bath under nitrogen. A solution of 4.0 moles of n-butyllithium was added dropwise over 1 hour maintaining a temperature below -58° C. to form an orange-yellow precipitate. After continued stirring in the cold for 15 minutes, 1280 g of tributyltin chloride was added over 2 hours at a temperature of -60° to -57° C. to form a solution. The reaction was stirred cold for 45 minutes before it was slowly (2 hours) warmed to 20° C. A portion of Super-Cel (100 g) was added and the reaction mixture was filtered to remove the precipitated lithium chloride. The cake was washed with diethyl ether (2×500 mL). After concentration to dryness a total of 1575 g (99.7% yield) of product was obtained which was used without further purification.
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