Dibromomethane → {1-Methyl-2-[(1,2,2-trimethylbicyclo[3.1.0]hex-3-yl)methyl]cyclopropyl}methanol

Participants

Reaction Steps

200 g (1.15 mol) of dibromomethane and 1 ml (0.013 mol) of acetyl bromide were added successively to a suspension of 85 g (1.3 mol) of zinc powder and 12 g (83 mmol) of finely ground cuprous bromide in 250 ml of anhydrous diethyl ether. The reaction mixture was stirred until its color changed from grey to black (-30 minutes). After addition of 50 g (0.26 mol) of (E)-2-methyl-4-(2,2,3-trimethylcyclopent-3-enyl)but-2-en-1-ol dissolved in 50 ml of the same solvent (Et2O), in 10 minutes (the exothermic reaction triggers a smooth reflux of ether), and 2 drops of TiCl4, stirring at room temperature was continued for further 7 hours. The reaction mixture was then diluted with 300 ml of MTBE, filtered through Celite, the filtrate washed with 200 ml of ice-cold 0.1N HCl and 3×200 ml of brine, dried (MgSO4), concentrated in vacuo and distilled rapidly (0.1 Torr) to give 39 g of a yellowish oil containing 81% of [1-methyl-2-(1,2,2-trimethyl-bicyclo[3.1.0]hex-3-yl-methyl)cyclopropyl]methanol (yield 55%). Further purification by distillation using a 15 cm Vigreux column under 0.08 Torr afforded 27.4 g (48% yield) of olfactorily pure product. GC purity >91%, b.p. 104-105° C./0.08 Torr. More product could be recovered from 4.5 g of rejected (66% pure) fractions.

Provenance & Evidence