BITHIENOLs: Promising C2-Symmetric Biheteroaromatic Diols for Organic Transformation

Sara Gabrieli, Roberto Cirilli, Tiziana Benincori, Marco Pierini, Simona Rizzo, Sergio Rossi

Research output: Contribution to journalArticle

Abstract

2,2′,5,5′-Tetraphenyl-3,3′-bithiophene-4,4′-diol, the first member of a new class of chiral C2-symmetric atropisomeric diols based on a biheteroaromatic scaffold, has been synthesized. Dynamic enantioselective HPLC experiments revealed a racemization barrier of 22.9 kcal/mol at 25 °C, which is high enough to permit the chromatographic collection of both enantiomers on a semi-preparative scale, but at the borders of application as a promoter in asymmetric catalysis. The ground and transition states involved in the enantiomerization process have been identified through DFT calculations, which suggest the intermediacy of a tautomeric species in which a thiophen-3-ol unit and a 2,3-dihydrothiophen-3-one ring are present. The proposed racemization mechanism is supported by the results of dynamic HPLC experiments. Calculations also suggested which substituent groups at the 2,2′-positions of the thiophene rings could lead to an increase in enantiomerization barriers sufficient to confer full configurational stability on the 3,3′-bithiophene framework.

Original languageEnglish
Pages (from-to)861-870
Number of pages10
JournalEuropean Journal of Organic Chemistry
Volume2017
Issue number4
DOIs
Publication statusPublished - Jan 26 2017

Keywords

  • Alcohols
  • Atropisomerism
  • Biaryls
  • Chiral resolution
  • Racemization

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Organic Chemistry

Fingerprint Dive into the research topics of 'BITHIENOLs: Promising C<sub>2</sub>-Symmetric Biheteroaromatic Diols for Organic Transformation'. Together they form a unique fingerprint.

  • Cite this