Axially chiral pyridine compounds: Synthesis, chiral separations and determination of protonation dependent barriers to hindered rotation

Furkan Halis Isikgor, Sule Erol, Ilknur Dogan*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

12 Scopus citations

Abstract

Axially chiral enantiomeric 2-pyridylimino-3-pyridyl-thiazolidine-4-ones and -thiones have been synthesized and their rotational barriers around the N-3C(pyridyl) bond have been determined by variable temperature NMR or by thermal racemization of the micropreparatively resolved enantiomers. Rotational barriers of the unprotonated compounds ranged from 46 to 116 kJ/mol, depending on the substituent on the N-3-pyridyl ring and on the exocyclic oxygen or sulfur atoms of the thiazolidine ring. Protonation of the pyridine nitrogens by TFA caused a decrease in the barrier to the rotation by stabilizing the transition state of the rotations via hydrogen bonding interactions.

Original languageEnglish (US)
Pages (from-to)449-456
Number of pages8
JournalTetrahedron Asymmetry
Volume25
Issue number5
DOIs
StatePublished - Mar 15 2014

Bibliographical note

Funding Information:
This project was supported by the Boğaziçi University research fund (BAP) with project numbers 10B05P6 and 13B05P5.

ASJC Scopus subject areas

  • Catalysis
  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Inorganic Chemistry

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