(+)-(1S,4R)-P-MENTHA-2,8-DIEN-1-OL CAS 22972-51-6

A synthesis technique of (1S,4R)-1-methyl-4-(1-methylvinyl)-2-cyclohexen-1-ol, comprising the steps:

(1) 1.2Kg (+)-limonene, 12L dichloromethane and 185g sodium bicarbonate were added to the 20L there-necked flask, after being cooled to 0°C, 1.78Kg m-chloroperoxybenzoic acid was added in three batches, and the internal temperature was controlled to 5 Within ℃, the stirring reaction was completed for 2 hours, quenched by adding 23% aqueous sodium sulfite solution, stirring and separating, the organic phase was washed once with 13% aqueous sodium sulfite solution and then concentrated to obtain 1.38Kg of crude product (trans 1,2- The purity of epoxylimonene is 46%, and the yield is over 100%; cis-1,2-epoxylimonene:trans-1,2-epoxylimonene=1:1).

(2) under nitrogen protection, 1.4Kg of diphenyl diselenide and 13L of absolute ethanol were mixed, cooled to 8°C, 400g of sodium borohydride was added in batches within 10°C of temperature control, and after stirring for 1 hour, the above 1, 2-epoxylimonene was added dropwise, and after dropping, the temperature was raised to 80°C and refluxed for 4 hours; the reaction was stopped, and the temperature was lowered to 6°C;

(3) dropwise add 3.2L of anhydrous tetrahydrofuran to the reaction system of step (2), and continue to dropwise add 30% hydrogen peroxide 1.17Kg at the above-mentioned temperature, be warming up to 20° C. after the dropwise addition, and stir for 6 hours; add water and leave standstill Separation, the aqueous phase was extracted with n-hexane, the organic phases were combined and washed with 10% sodium carbonate aqueous solution and saturated brine, and then concentrated to remove the organic solvent, ethanol was added to the concentrated solution, concentrated again, and the operation was repeated twice, and then cooled to 0-5 ° C , stirred for 3 hours, filtered to obtain a filter cake, added the filter cake to 10 L of chloroform, heated to 62°C under reflux for overnight reaction, and then distilled under reduced pressure to obtain (1S,4R)-1-methyl-4-(1-methyl) Vinyl)-2-cyclohexen-1-ol 582g (purity 80.8%, ee% 99.2%, de% 84.3%).