[Li+].CC([N-]C(C)C)C.[CH2:9]([O:16][CH2:17]CC1CCC(=O)CC1)[C:10]1[CH:15]=[CH:14][CH:13]=[CH:12][CH:11]=1.CN(P(N(C)C)(N(C)C)=[O:30])C.C(C(OC)=O)#N>C1COCC1>[CH3:17][O:16][C:9]([CH:10]1[CH2:15][CH2:14][CH2:13][CH2:12][CH2:11]1)=[O:30]
A solution of LDA (33 ml, 1.5 M in Et2O) in THF (50 mL) at −78° C. was treated with 4-(2-benzyloxy-ethyl)-cyclohexanone (9.5 g, 40.2 mmol). The mixture was warmed to 0° C. over 30 min. before re-cooling to −78° C. and adding HMPA (7 mL). Methyl cyanoformate (CNCO2Me, 4.1 mL, 85 mmol) was added and the mixture was stirred for 15 m before aqueous quench and work-up. The product was purified by chromatography on SiO2 with 10% EtOAc:Hx. 5-(2-Benzyloxy-ethyl)-2-oxo-)cyclohexanecarboxylic acid methyl ester was isolated, 5.8 g (49%).
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