Enzymatic Desymmetrization of meso-2,6-Dimethyl-1,7-heptanediol. Enantioselective Formal Synthesis of the Vitamin E Side Chain and the Insect Pheromone Tribolure
摘要:
The chiral syn-1,5-dimethylalkyl subunit is found in many natural products with significant biological activities. Enzymatic esterification of meso-2,6-dimethyl-1,7-heptanediol with isopropenyl acetate in the presence of Pseudomonas cepacia lipase in organic medium provided the chiral nonracemic monoester in high enantiomeric excess (ee = 95%). This chiral building block was used in the formal syntheses of vitamin E side chain and the insect pheromone tribolure.
Synthesis of (3S,7S)- and (3S,7S,15S)- Stereoisomers of 3,7-Dimethyl-2-heptacosanone and 3,7,15-Trimethyl-2-heptacosanone, the Ketones Identified from the LocustSchistocerca gregaria
The (3S,7S) and (3S,7S,15S) stereoisomers of 3,7-dimethyl-2-heptacosanone (1) and 3,7,15-trimethyl-2-heptacosanone (2), the ketones identified from the locust Schistocerca gregaria, were synthesized by employing (2R,6S)-7-acetoxy-2,6-dimethyl-1-heptanol (4) as the starting material.