C(Cl)(C)C.[Mg].C(O[C:10]([CH3:14])([CH3:13])[CH:11]=[CH2:12])(=O)C.[C:15]([CH2:17][C:18]([O:20][CH2:21][CH3:22])=[O:19])#[N:16].[H-].[Na+].[Cl-].[NH4+]>CCOCC.O1CCCC1>[C:15]([CH:17]([C:10]([CH3:14])([CH3:13])[CH:11]=[CH2:12])[C:18]([O:20][CH2:21][CH3:22])=[O:19])#[N:16]A mixture of 131 mg of dichloro(bis triphenylphosphine)nickel II, 1.5 ml of tetrahydrofuran and 372 μl of a 1.08N solution of magnesium isopropyl chloride in ether was stirred at room temperature for 10 minutes and then a solution of 128 mg of 3-acetoxy-3-methyl-but-1-ene in 2 ml of tetrahydrofuran was added thereto followed by addition of a suspension of 248 mg of ethyl cyanoacetate, 88 mg of a 55% dispersion of sodium hydride in oil and 6 ml of tetrahydrofuran. The mixture was stirred at room temperature for 48 hours and a solution of ammonium chloride was added thereto. The mixture was extracted with ether and the decanted organic phase was dried and evaporated to dryness under reduced pressure. The residue was chromatographed over silica gel and eluted with a 1--1 ether-petroleum ether mixture to obtain 126 mg of ethyl 2-cyano-3,3-dimethyl-pent-4-en-1-oate containing 95% of the desired isomer and 5% of ethyl 2-cyano-5-methyl-hex-4-en-1-oate.
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