Radical-mediated C–H functionalization: a strategy for access to modified cyclodextrins

Dimitri Alvarez-Dorta, Elisa I. León, Alan R. Kennedy, Angeles Martin, Inés Pérez-Martín, Ernesto Suárez

Research output: Contribution to journalArticle

4 Citations (Scopus)
13 Downloads (Pure)

Abstract

A simple and efficient radical C–H functionalization to access modified cyclodextrins (CDs) has been developed. The well-defined conformation of glycosidic and aglyconic bonds in α-, β-, and γ-CDs favors the intramolecular 1,8-hydrogen atom transfer (HAT) promoted by the 6I-O-yl radical, which abstracts regioselectively the hydrogen at C5II of the contiguous pyranose. The C5II-radical evolves by a polar crossover mechanism to a stable 1,3,5-trioxocane ring between two adjacent glucoses or alternatively triggers the inversion of one α-d-glucose into a 5-C-acetoxy-β-l-idose unit possessing a 1C4 conformation. The 6I,IV- and 6I,III-diols of α- and β-CDs behave similarly to the monoalcohols, forming mostly compounds originating from two 1,8-HAT consecutive processes. In the case of 6I,II-diols the proximity of the two 6-O-yl radicals in adjacent sugar units allows the formation of unique lactone rings within the CD framework via a 1,8-HAT−β-scission tandem mechanism. X-ray diffraction carried out on the crystalline 1,4-bis(trioxocane)-α-CD derivative shows a severe distortion toward a narrower elliptical shape for the primary face.
Original languageEnglish
Pages (from-to)11766-11787
Number of pages22
JournalJournal of Organic Chemistry
Volume81
Issue number23
DOIs
Publication statusPublished - 2 Nov 2016

Keywords

  • C–H functionalization
  • modified cyclodextrins
  • aglyconic bonds
  • glycosidic bonds
  • polar crossover mechanism
  • elliptical

Fingerprint Dive into the research topics of 'Radical-mediated C–H functionalization: a strategy for access to modified cyclodextrins'. Together they form a unique fingerprint.

Cite this