title: Reinvestigation of the Absolute Configurations of Chiral β-Mercaptoalkanones Using Vibrational Circular Dichroism and1H NMR Analysis.
abstract: The absolute configurations of chiral β-mercaptoalkanones were previously assigned on the basis of the1H NMR anisotropy method using (S)-2-methoxy-2-(1-naphthyl)propionic acid ((S)-MαNP) as the chiral auxiliary. This study presents a reinvestigation of the configurations of 4-mercapto-2-pentanone 1, 4-mercapto-2-heptanone 2, and 2-mercapto-4-heptanone 3. Enantiomers of 1, 2, and 3 were obtained by lipase-catalyzed hydrolyses of the respective acetylthioalkanones. Upon derivatization with (S)-MαNP, the configurations of the reaction products were deduced based on the order of the HPLC elution of the diastereoisomeric thioesters, assuming that the sector rule previously developed for secondary alcohols is also valid for thiols. In addition, the configurations were experimentally determined by vibrational circular dichroism (VCD) and1H NMR analyses after esterification with (R)-hydratropic acid (HTA) and 2-methoxy-2-phenylacetic acid (MPA). The assignments of the configurations using VCD and NMR analyses of HTA- and MPA-thioesters were in agreement. However, they were opposite to those deduced for (S)-MαNP thioesters via the sector rule. Consequently, the formerly assigned configurations of β-mercaptoalkanones deduced via investigation of (S)-MαNP-derivatives have to be revised.
authors: Lehrstuhl für Allgemeine Lebensmitteltechnologie, Technische Universität München , Maximus-von-Imhof-Forum 2, D-85354 Freising-Weihenstephan, Germany.
authors: Christiane
authors: C
authors: Kiske
authors: Lehrstuhl für Allgemeine Lebensmitteltechnologie, Technische Universität München , Maximus-von-Imhof-Forum 2, D-85354 Freising-Weihenstephan, Germany.
authors: Svenja
authors: S
authors: Nörenberg
authors: Lehrstuhl für Allgemeine Lebensmitteltechnologie, Technische Universität München , Maximus-von-Imhof-Forum 2, D-85354 Freising-Weihenstephan, Germany.
authors: Miriam
authors: M
authors: Ecker
authors: Lehrstuhl für Allgemeine Lebensmitteltechnologie, Technische Universität München , Maximus-von-Imhof-Forum 2, D-85354 Freising-Weihenstephan, Germany.
authors: Xingyue
authors: X
authors: Ma
authors: Frontier Research Center for Post-Genome Science and Technology, Faculty of Advanced Life Science, Hokkaido University , Kita 21 Nishi 11, Sapporo 001-0021, Japan.
authors: Tohru
authors: T
authors: Taniguchi
authors: Frontier Research Center for Post-Genome Science and Technology, Faculty of Advanced Life Science, Hokkaido University , Kita 21 Nishi 11, Sapporo 001-0021, Japan.
authors: Kenji
authors: K
authors: Monde
authors: Lehrstuhl für Biochemie, Technische Universität München , Lichtenbergstraße 4, D-85747 Garching, Germany.
authors: Wolfgang
authors: W
authors: Eisenreich
authors: Lehrstuhl für Allgemeine Lebensmitteltechnologie, Technische Universität München , Maximus-von-Imhof-Forum 2, D-85354 Freising-Weihenstephan, Germany.
authors: Karl-Heinz
authors: KH
authors: Engel
mesh_terms: D002942:Circular Dichroism; D007659:Ketones / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D009281:Naphthalenes / Q000737:chemistry; D010422:Pentanones / Q000737:chemistry*; D011422:Propionates / Q000737:chemistry; D013237:Stereoisomerism; D013438:Sulfhydryl Compounds / Q000737:chemistry
chemical_list: D007659:Ketones; D009281:Naphthalenes; D010422:Pentanones; D011422:Propionates; D013438:Sulfhydryl Compounds; C499260:2-methoxy-2-(1-naphthyl)propionic acid; C011917:2-heptanone; C076402:2-pentanone
keywords: 1H NMR spectroscopy; 2-mercapto-4-alkanones; 4-mercapto-2-alkanones; VCD; absolute configuration; lipase