Fragmentation Reactions

T. T. Hoang, G. B. Dudley, L. J. Williams

Research output: Chapter in Book/Report/Conference proceedingChapter

14 Scopus citations


Fragmentations as defined by Grob are heterolytic bond-cleavage reactions in which a molecule breaks into three (or more) fragments derived from an electrofuge, middle part, and nucleofuge. Concerted bond-cleavage events involve parallel alignment of the cleaving bonds in well-ordered transition states. This chapter provides first an introductory overview of fragmentation reactions in organic synthesis, then a historical perspective on their development, and a mechanistic framework for interpreting and predicting fragmentation behavior. Synthetic applications are organized according to what arises from the middle part (middle part→alkenes, alkynes, or allenes), and are presented based on the fragmentation results in a skeletal degradation, ring opening, or ring expansion. The Beckmann fragmentation (middle part→nitrile) is presented separately. Practical considerations such as conformational requirements and appropriate choice of nucleofuge for various applications in synthesis are discussed in context and are summarized at the end.

Original languageEnglish (US)
Title of host publicationHeteroatom Manipulation
PublisherElsevier Ltd
Number of pages19
ISBN (Print)9780080977430
StatePublished - Feb 2014

All Science Journal Classification (ASJC) codes

  • Chemical Engineering(all)
  • Chemistry(all)


  • Bond cleavage
  • Decarboxylation
  • Elimination
  • Fragmentation
  • Ring expansion
  • Ring opening


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