a Farnesol → 1-Chloro-3,7,11-trimethyldodeca-2,6,10-triene

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Reaction Steps

A 3-N 100 mL flask was charged with PCl3 (2.8 mL, 31.6 mmol) and dry DMF (32 mL) then stirred at RT for 1 h. In a separate 50 mL flask, farnesol (Ex-1B-5) (10.0 g, 45.2 mmol) and DMF (10 mL) was charged. The PCl3/DMF solution was then transferred to the farnesol, solution and the resulting dark orange solution was stirred for 1 h. The reaction was quenched by addition of solid NaHCO3 (2.5 g, 63.2 mmol). The solvent was removed by high vacuum rotary evaporation to yield an oily orange residue. To the residue was added MTBE (40 mL) and water (40 mL). The aqueous phase was washed with MTBE (3×20 mL). The MTBE layers were combined, washed with brine (2×20 mL), dried over MgSO4, filtered and finally concentrated by rotary evaporation to yield 1-chloro-3,7,11-trimethyl-dodeca-2,6,10-triene (Ex-1B-6) as a yellow oil (9.89 g, 92%). 1H NMR (400 MHz, CDCl3) δ (ppm): 5.47 (broad-t, J=8.3 Hz, 1H), 5.15-5.07 (m, 2H), 4.12 (d, J=8.1 Hz, 2H), 2.18-1.95 (m, 8H), 1.75 (s, 3H), 1.70 (s, 3H), 1.62 (s, 6H).

Provenance & Evidence