Preparation of single-enantiomer 2-methyl-4-heptanol, a pheromone of Metamasius hemipterus, using (S)-2-methoxy-2-(1-naphthyl)propionic acid.
To investigate the resolution of secondary alcohols using 2-methoxy-2-(1-naphthyl)propionic acid (MalphaNP acid), 2-methyl-4-heptanol, one of the aggregation pheromones of Metamasius hemipterus, was resolved using (S)-MalphaNP acid. As a chiral-resolving agent, MalphaNP acid is superior to 3,3,3-trifluoro-2-methoxy-2-phenylpropionic acid (MTPA) in terms of HPLC separation and NMR shielding. A better separation of diastereomeric MalphaNP esters was observed when n-hexane-THF was used as the eluent for silica gel HPLC. The solvolysis of the diastereomeric MalphaNP esters gave (R)-2-methyl-4-heptanol and its enantiomer; enantiopure (S)-MalphaNP acid was also recovered. In addition, the preferred conformation of the MalphaNP ester was confirmed using methyl (R)-3-hydroxyvalerate as an authentic compound.
Ichikawa
Akio
A
National Institute of Agrobiological Sciences, 1-2 Owashi, Tsukuba, Ibaraki 305-8634, Japan. ichikawa@affrc.go.jp
Ono
Hiroshi
H
D000818:Animals; D001517:Coleoptera / Q000737:chemistry*; D019850:Heptanol / Q000031:analogs & derivatives* / Q000737:chemistry; D009281:Naphthalenes / Q000737:chemistry*; D010675:Pheromones / Q000737:chemistry*; D011422:Propionates / Q000737:chemistry*; D013057:Spectrum Analysis / Q000379:methods*; D013237:Stereoisomerism; D013438:Sulfhydryl Compounds
C473088:2-methyl-4-heptanol; D009281:Naphthalenes; D010675:Pheromones; D011422:Propionates; D013438:Sulfhydryl Compounds; C499260:2-methoxy-2-(1-naphthyl)propionic acid; D019850:Heptanol