[CH3:1][O:2][C:3]1[C:10]([CH2:11]Cl)=[C:9]([CH3:13])[C:6]([O:7][CH3:8])=[C:5]([CH3:14])[C:4]=1[CH3:15].[Mg].[CH2:17](Br)[C:18]#[CH:19]>C1COCC1.CCOCC.[I-].[Na+]>[CH2:11]([C:10]1[C:3]([O:2][CH3:1])=[C:4]([CH3:15])[C:5]([CH3:14])=[C:6]([O:7][CH3:8])[C:9]=1[CH3:13])[CH2:19][C:18]#[CH:17]A solution of chloromethyltrimethylhydroquinone dimethyl ether (7.5 g; 32 mmol) in THF (20 ml) was treated dropwise at 0° with a freshly Prepared solution of a Grignard reagent Prepared from 1.9 g of magnesium shavings and 4.91 ml (65 mmol) of propargyl bromide. After the addition of solid sodium iodide (0.42 g) the mixture was warmed to room temperature and stirred overnight. Thereafter, the reaction mixture was diluted with ether and washed with 2N hydrochloric acid. The ethereal solution was deacidified with bicarbonate, dried and freed from solvent. Distillation (0.04 mbar; 140° C.) of the residue gave 7.16 g of 1-(3-butynyl)-3,6-dimethoxy-2,4,5-trimethylbenzene; melting point: 54° C.
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