[C:1]([C:3]1[CH:8]=[CH:7][CH:6]=[CH:5][N:4]=1)#[CH:2].[CH3:9][C@@H:10]1[CH2:15][CH2:14][CH2:13][C:12](=O)[CH2:11]1>>[CH3:9][C@H:10]1[CH2:11][C:12]([C:2]#[C:1][C:3]2[CH:8]=[CH:7][CH:6]=[CH:5][N:4]=2)=[CH:13][CH2:14][CH2:15]1.[CH3:9][C@@H:10]1[CH2:15][CH2:14][CH2:13][C:12]([C:2]#[C:1][C:3]2[CH:8]=[CH:7][CH:6]=[CH:5][N:4]=2)=[CH:11]1Reactants: 2-ethynylpyridine (6.0 mmol, 618 mg), (3R)-(+)-3-methylcyclohexanone (6.0 mmol, 0.73 mL); yields 2-{[(5R)-5-methyl-1-cyclohexen-1-yl]ethynyl}pyridine and 2-{[(3R)-3-methyl-1-cyclohexen-1-yl]ethynyl}pyridine (1:1) as a transparent yellow oil (440 mg, 37% overall yield) as a mixture of regioisomers. 1H NMR (CDCl3, 300 MHz) Δ8.56 (m, 1H), 7.62 (m, 1H), 7.40 (m, 1H), 7.18 (m, 1H), 6.31 (m, 0.5H), 6.19 (m, 0.5H), 2.30 (m, 3H), 1.85 (m, 2.5H), 1.22 (m, 1H), 0.98 (m, 3.5H). MS (EI ionization) 197 (M+) two peaks resolved.
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