Water → HCID 78137770, compound

Participants

Reaction Conditions

Reaction Steps

To a 500 mL three-neck reaction flask protected from atmospheric moisture by nitrogen gas throughout the course of the reaction a solution of 2.4 g potassium tert-butoxide (0.11 mol) in 60 mL of anhydrous tetrahydrofuran was added. Then 29.2 g of diethyl 3,7-dimethyl-2,6-octadienyl-phosphonate (3B) (0.10 mol) was added dropwise over 30 min under mechanical stirring by use of an external cold bath to maintain the internal temperature of approximately −30 to −25° C., and the reaction mixture was subsequently stirred in the cold for 60 min to ensure the formation of carbanion thoroughly. Then 16 g of 2-methyl-3,3-diethoxy-1-propanal (4B) (0.10 mol)) was added dropwise at −30˜−25° C. over 1 h and the reaction mixture was subsequently stirred for 30 min at this temperature until the reaction completed according to GC. Followed by the addition of 50 mL water and 100 mL ether and stirring for 10 min, after stratification, the organic layer was washed with 5% aqueous sodium chloride (3×25 mL), then dried over anhydrous magnesium sulfate and subsequently filtered. Removal of the volatile organic solvents in vacuo, the residue subsequently was fractional distillated to afford 19.7 g of (5-E and 5-Z)-2,6,10-trimethyl-1,1-diethoxy-3,5,9-undecatriene (2D) of 99-103° C./1 mmHg, as a colorless liquid with GC content of 94.2% (total content of cis and trans) and the yield of 66.3%. There are 2 peaks according to GC and GC-MS. ascertained is the same with that of Example IV

Provenance & Evidence