3. Photogeneration of Heteroatom-Centered Radicals

  1. Angelo Albini and
  2. Maurizio Fagnoni

Published Online: 12 JUL 2013

DOI: 10.1002/9781118689202.ch03

Photochemically-Generated Intermediates In Synthesis

Photochemically-Generated Intermediates In Synthesis

How to Cite

Albini, A. and Fagnoni, M. (eds) (2013) Photogeneration of Heteroatom-Centered Radicals, in Photochemically-Generated Intermediates In Synthesis, John Wiley & Sons, Inc., Hoboken, New Jersey. doi: 10.1002/9781118689202.ch03

Editor Information

  1. PhotoGreen Lab, Department of Chemistry, University of Pavia, Pavia, Italy

Publication History

  1. Published Online: 12 JUL 2013
  2. Published Print: 23 AUG 2013

ISBN Information

Print ISBN: 9780470915349

Online ISBN: 9781118689202

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Keywords:

  • heteroatom-centered radicals (Y.);
  • IVA group elements;
  • photogeneration;
  • VA group elements;
  • VIA group elements;
  • VIIA group atoms

Summary

Heteroatom-centered radicals (Y.) are useful intermediates in organic synthesis and, in analogy to carbon-centered radicals, can be generated by a photohomolytic cleavage. All of the radicals Y. deriving from elements belonging to the IVA—VIIA group elements are accessible by homolytic scission of a bond between two heteroatoms (Y—W), as it happens in Barton esters (N—O), in N-haloamines or N-haloamides (N—X), in disulfides (S—S), or in dihalogens (X—X). Cleavage of a Y—H bond (path b) through the action of a suitable photoinitiator (PI, path b') is all important for P—H (in disubstituted phosphines) and S—H (in thiols) bonds. This chapter describes synthetic applications of photogenerated heteroatom centered radicals excluding polymerization reactions. In some cases radical Y. promotes a process but it is not incorporated in the end product, as happens in the radical oxidation initiated by a halogen radical. This type of reaction is mentioned briefly with some examples.