Dimethyl Sulfate → 2,6-Dimethyl-2-methoxyhept-5-ene

Reaction equation

[H-].[Na+].[CH3:3][C:4]([OH:12])([CH2:6][CH2:7][CH:8]=[C:9]([CH3:11])[CH3:10])[CH3:5].[CH3:13]OS(OC)(=O)=O>O1CCCC1>[CH3:3][C:4]([O:12][CH3:13])([CH2:6][CH2:7][CH:8]=[C:9]([CH3:11])[CH3:10])[CH3:5]

Participants

Procedure

To sodium hydride (93.5 g, 3.9 mol) suspended in tetrahydrofuran (300 mL) was added 2,6-dimethylhept-5-en-2-ol (500 g, 3.5 mol) in tetrahydrofuran (1000 mL). The mixture was heated at reflux until gas evolution was complete. Dimethylsulfate (274 mL, 2.9 mol) in tetrahydrofuran (226 mL) added to the cold (0~C.) mixture. After standing for 16 h, the mixture was heated at reflux for 7 hours. Aqueous workup yielded 2,6-dimethyl-2-methoxyhept-5-ene, bp40 65-68~C. (461.5 g); NMR(CDCl3) 1.2(s,6H), 1.4-1.6(m,2H), 1.6(s,3H), 1.7(s,3H), 1.9-2.1(m,2H), 3.2(s,3H), 5.1-5.2(m,1H); IR(neat) 2970, 2932, 1462, 1442, 1373, 1357, 1195, 1072 cm-1 ; MS(m/e) 41, 67, 73, 109, 124, 142.