C([N-]C(C)C)(C)C.[Li+].O1CCCC1.[C:14]1([C:20]#[CH:21])[CH:19]=[CH:18][CH:17]=[CH:16][CH:15]=1.CON(C)[C:25](=[O:32])[C:26]1[CH:31]=[CH:30][CH:29]=[CH:28][CH:27]=1>C1CCCCC1>[C:26]1([C:25](=[O:32])[C:21]#[C:20][C:14]2[CH:19]=[CH:18][CH:17]=[CH:16][CH:15]=2)[CH:31]=[CH:30][CH:29]=[CH:28][CH:27]=1
Place lithium diisopropylamide (10 mL of a 1.5M solution in cyclohexane) and tetrahydrofuran (40 mL) under an argon atmosphere and cool to 0° C. Add, by dropwise addition, phenylacetylene (1.65 mL, 15 mmol). Remove the cooling bath and stir for 30 minutes as room temperature. Cool the yellow solution to 0° C. and add, by dropwise addition, N-methoxy-N-methylbenzamide (3.04 mL, 20 mmol). Remove the cooling bath and stir for 30 minutes at room temperature. Pour onto ethyl ether and water, separate the organic phase and dry (MgSO4). Filter and evaporate the solvent in vacuo to yield an oil. Purify by silica gel chromatography (2% ethyl acetate/hexane) then purify further by distillation (2×) to yield 1.9 g of the title compound; bp 210° C. in vacuo.
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