C(NC(C)C)(C)C.[Li+].CCC[CH2-].[CH2:13]([O:15][C:16](=[O:24])[CH2:17][CH:18]1[CH2:23][CH2:22][CH2:21][CH2:20][CH2:19]1)[CH3:14].CN1C(=O)N(C)CCC1.Br[CH2:35][CH2:36][Cl:37]>C1COCC1>[CH2:13]([O:15][C:16](=[O:24])[CH:17]([CH:18]1[CH2:23][CH2:22][CH2:21][CH2:20][CH2:19]1)[CH2:35][CH2:36][Cl:37])[CH3:14]Diisopropylamine (2.71 ml, 1.1 eq.) was added to dry THF (10 ml) and cooled to -78° C. N-Butyllithium (11.01 ml of 1.6 Molar solution, 1.0 eq.) was added and the mixture stirred at -78° C. for 0.5 hour. To this mixture was then added dropwise a solution of ethyl-2-cyclohexylacetate (3.0 g, 1.0 eq.) in THF (20 ml) at -78° C. and stirred for 0.5 hour. DMPU (2.13 ml, 1.0 eq.) in THF (20 ml) was added dropwise and allowed to stir at -78° C. for 10 minutes. To this mixture was added 1-bromo-2-chloroethane (1.46 ml, 1.0 eq.) in THF (10 ml) and the mixture stirred at -5° C. for 15 minutes. The mixture was then warmed to room temperature and stirred for 1.0 hour. The mixture was cooled to 0° C., quenched with saturated ammonium chloride solution, extracted with ethyl ether and the ether layer was washed three times with water. The organic layer was separated, dried over K2CO3 and the solvent removed to provide 3.6 g of product. This was fractionally distilled to provide 3.0 g of product Boiling Point 66°-70° C. at 0.05 mmHg.
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