Chiral photochemistry in a confined space: torquoselective photoelectrocyclization of pyridones within an achiral hydrophobic capsule

Arun Kumar Sundaresan, Corinne L D Gibb, Bruce C. Gibb, Vaidhyanathan Ramamurthy

Research output: Contribution to journalArticle

30 Scopus citations

Abstract

Chiral induction during the photoelectrocyclization of pyridones included within octa acid (OA) capsule has been established. Chiral induction is brought about by a chiral auxiliary appended to the reactive pyridone moiety. Importantly, the same chiral auxiliary while ineffective in acetonitrile solution is found to be effective within the confined space of OA capsule. The diastereomeric excess of 92% obtained here is comparable only to that in solid state. OA capsule, we believe, provides restriction to the rotational motions of the reactant pyridone and chiral auxiliary and thus places the chiral auxiliary in a selective conformation with respect to the reactive pyridone part. A correlation between the position of the methyl group on the pyridone ring and diastereoselectivity was noted. Structures of the host-guest complexes were examined by 1H NMR and the data were used to obtain preliminary information concerning the mechanism of chiral induction within the confined spaces of OA capsule.

Original languageEnglish
Pages (from-to)7277-7288
Number of pages12
JournalTetrahedron
Volume65
Issue number35
DOIs
StatePublished - Aug 29 2009

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Keywords

  • Chiral photochemistry
  • Confined space
  • Electrocyclization
  • Host-guest
  • Pyridones
  • Supramolecular assemblies

ASJC Scopus subject areas

  • Biochemistry
  • Organic Chemistry
  • Drug Discovery

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