title: Synthesis and analysis of the all-(S) side chain of phosphomycoketides: a test of NMR predictions for saturated oligoisoprenoid stereoisomers.
abstract: (4S,8S,12S,16S,20S)-Pentamethylheptacosan-1-ol has been synthesized and analyzed by resolution-enhanced NMR spectroscopy with the aid of a recent set predicted spectra of all its stereoisomers. The configuration was confirmed, but isomer purity of the sample (~70%) was lower than expected. A truncated analogue, (2S,6S,10S,14S)-2,6,10,14-tetramethylhenicosan-1-ol TBDPS ether, was prepared from a late stage synthetic intermediate. Analysis of its spectra confirmed the configuration and showed that the sample was isomerically pure. The results suggest that a late-stage epimerization, not a failure of an asymmetric synthesis step, caused the formation of minor stereoisomers in the sample of pentamethylheptacosan-1-ol. The study shows the value of the predicted set of oligoisoprenoid spectra and further extends the predictive model to a new subclass of compounds.
authors.affiliation: Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Buter
authors.forename: Edmund A-H
authors.initials: EA
authors.lastname: Yeh
authors.forename: Owen W
authors.initials: OW
authors.lastname: Budavich
authors.forename: Krishnan
authors.initials: K
authors.lastname: Damodaran
authors.forename: Adriaan J
authors.initials: AJ
authors.lastname: Minnaard
authors.forename: Dennis P
authors.initials: DP
authors.lastname: Curran
mesh_terms: D005233:Fatty Alcohols / Q000032:analysis* / Q000138:chemical synthesis* / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D013237:Stereoisomerism; D013729:Terpenes / Q000737:chemistry*
chemical_list: D005233:Fatty Alcohols; D013729:Terpenes