7. Photogeneration of Carbenes and Nitrenes

  1. Angelo Albini and
  2. Maurizio Fagnoni

Published Online: 12 JUL 2013

DOI: 10.1002/9781118689202.ch07

Photochemically-Generated Intermediates In Synthesis

Photochemically-Generated Intermediates In Synthesis

How to Cite

Albini, A. and Fagnoni, M. (eds) (2013) Photogeneration of Carbenes and Nitrenes, in Photochemically-Generated Intermediates In Synthesis, John Wiley & Sons, Inc., Hoboken, New Jersey. doi: 10.1002/9781118689202.ch07

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



  • acylnitrenes;
  • benzoazirine;
  • cycloaddition;
  • dehydroazepine;
  • intramolecular trapping;
  • ketenes;
  • nitrenes;
  • photogenerated carbenes;
  • silyloxy carbenes;
  • Wolff rearrangement


Carbenes and nitrenes exist in two multiplicities, singlet and triplet, that exhibit a quite different chemistry. The mode of generation, thermal or photochemical, has a paramount role in determining which spin state will be arrived at. This chapter talks about structural and chemical behavior of carbenes. First, it discusses cycloaddition through photogenerated carbenes. Second, the chapter describes C—H and C—C insertion of carbenes. Most interesting from the synthetic point of view is the Wolff rearrangement of a-diazoketones to give ketenes. Next, the chapter explains silyloxy carbenes, which are conveniently prepared through photochemical Brook rearrangement of acylsilanes and are useful intermediates in synthesis. Further, it presents structure, reactivity and intermolecular trapping of nitrenes. The chapter also highlights that intermolecular trapping of the dehydroazepine and/or the benzoazirine are the most effective reactions from the azides in terms of yield, particularly with electron poor derivatives. Finally, it deals with intramolecular trapping and acylnitrenes.