Related Experiment Video
Updated: Jul 22, 2026

Generation of Null Mutants to Elucidate the Role of Bacterial Glycosyltransferases in Bacterial Motility
Published on: March 11, 2022
Three challenges toward the assignment of absolute configuration of gymnocin-B
Katsunori Tanaka1, Yasuhiro Itagaki, Masayuki Satake
1Department of Chemistry, Columbia University, 3000 Broadway, New York, New York 10027, USA.
Abstract:
The absolute configuration of gymnocin-B has been determined to be (S)-10 and (S)-37. Three challenges toward the configurational assignment of this largest of the polyether marine toxin include (i) introduction of p-(meso-triphenylporphyrin)-cinnamate group (TPPcinnamate) on sterically hindered 10-, 37-hydroxyls under mild conditions, (ii) conformational analysis in the presence of TPPcinnamates at C-10 and C-37 positions on the flexible seven-membered rings embodied in a large polyether ladder-like scaffold structure, and (iii) determination of the chirality at C-10 and C-37 on the basis of porphyrin/porphyrin circular dichroism exciton-coupled interaction over a large distance. The experimentally obtained positive exciton couplet by CD and FDCD of the bis-TPPcin derivative of gymnocin-B is in good agreement with that of theoretically calculated CD of the MMFF optimized structures, by employing DeVoe's coupled oscillator approach, thus establishing the full absolute configuration of gymnocin-B.
More Related Videos
Related Concept Videos
Conformations of Cyclohexane
The chair form is the most stable and derives its name from its resemblance to the “easy chair.” In the chair conformation, two carbon atoms are arranged out-of-plane — one above and one below, minimizing the torsional strain. In the chair form, the bond angle is very close to the ideal tetrahedral value,...
Chair Conformation of Cyclohexane
The hydrogen atoms linked to carbons are arranged in two different axial and equatorial orientations to achieve this staggered...
Stereoisomerism of Cyclic Compounds
Chirality at Nitrogen, Phosphorus, and Sulfur
A consequence of chirality is the need for enantiomeric resolution. While this is theoretically possible for all...
Prochirality
Production of Antibiotics

