1-Chloro-3,7,11-trimethyldodeca-2,6,10-triene → 6,10,14-Trimethyl-5,9,13-pentadecatrien-1-ol

Beteiligte Stoffe

Reaktionsschritte

A solution of 37.5 mL (20.3 mmol, 5.1 eq.) of a 0.54M solution of Grignard reagent (Part (2)) in tetrahydrofuran and 9 mL of hexamethylphosphoramide at room temperature under argon was treated over 10 minutes with a solution of 955.5 mg (3.97 mmol) of farnesyl chloride (Part (1)) in 5 mL of tetrahydrofuran. After one hour, the reaction mixture was diluted with a mixture of 1:1 diethyl ether:hexane and quenched with 1M HCl. The organic phase was washed with three 25 mL portions of saturated NaHCO3, three 25 mL portions of H2O, and 25 mL of brine, dried over MgSO4 and evaporated to obtain 995.0 mg of crude product. Purification required two chromatographies. The first was run on 70 g of silica gel, eluting with 1:99 ethyl acetate:CH2Cl2 to provide 484.3 mg of impure material and 307.7 mg of pure title compound. The second chromatography, of the impure fractions, on 50 g of silica gel eluted with 0.75:99.25 ethyl acetate:CH2Cl2 gave 117.2 mg of slightly impure material and 302.8 mg of pure title compound. Combination of pure material from both columns gave a yield of 610.5 mg (58%) of pure desired title isomer.

Herkunft & Nachweise