[CH2:1]([O:3][C:4](=[O:13])[C:5]([C:11]#[N:12])=[CH:6][CH2:7][CH:8]([CH3:10])[CH3:9])[CH3:2].[N+]([CH3:17])([O-])=O.C1CCN2C(=NCCC2)CC1>C(#N)C>[CH2:1]([O:3][C:4]([C:5]1([C:11]#[N:12])[CH2:17][CH:6]1[CH2:7][CH:8]([CH3:10])[CH3:9])=[O:13])[CH3:2]To a solution of 2-cyano-5-methyl-hex-2-enoic acid ethyl ester (0.74 g, 4.08 mmol) in 16 mL acetonitrile was added nitromethane (1.11 mL, 20.4 mmol), followed by DBU (0.61 mL, 4.08 mmol) resulting in an orange solution. The reaction was heated to 60° C. for 16 hours, then cooled and partitioned between Et2O and 1N HCl (aq). The phases were separated, and the organic phase washed with brine, dried (MgSO4), and concentrated. Flash chromatography of the residue (5→10% EtOAc/hexanes) afforded 0.56 g (70%) of 1-cyano-2-isobutyl-cyclopropanecarboxylic acid ethyl ester as a pale yellow oil. 1H NMR (CDCl3) δ 4.22 (m, 2H), 1.75–1.90 (m, 3H), 1.63 (m, 1H), 1.36 (m, 2H), 1.30 (t, J=7.3 Hz, 3H), 0.95 (m, 6H). 13C NMR δ 168.25, 117.72, 62.94, 39.12, 30.25, 28.12, 25.66, 22.63, 22.40, 19.56, 14.30. LRMS: m/z 196.0 (M+1). Anal. Calcd for C11H17NO2: C, 67.66; H, 8.78; N, 7.17. Found: C, 67.32; H, 8.74; N, 7.32.
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