Synthesis
DOI: 10.1055/a-2707-7636
Paper

Ring-Strain Effects in Sommelet–Hauser Rearrangement of Five- and Six-Membered Fused Bicyclic Ammonium Ylides

Authors

  • Eiji Tayama

    1   Department of Chemistry, Faculty of Science, Niigata University, Niigata, Japan (Ringgold ID: RIN12978)
  • Kei Itoyama

    2   Graduate School of Science and Technology, Niigata University, Niigata, Japan (Ringgold ID: RIN12978)
  • Junto Sasazaki

    1   Department of Chemistry, Faculty of Science, Niigata University, Niigata, Japan (Ringgold ID: RIN12978)


Graphical Abstract

Abstract

The base-induced Sommelet–Hauser (S–H) rearrangement of N-benzylic 5,5- and 6,5-fused bicyclic ammonium salts proceeded over the [1,2]-Stevens rearrangement. The ring strain resulting from the fused bicyclic ammonium ylide generated destabilized the enolate form, increasing the contribution of the carbanion form. Therefore, the initial dearomative [2,3]-sigmatropic reaction proceeded smoothly to give the S–H rearrangement products. The products, α-arylamino acid amide derivatives, were obtained in pure enantio- and diastereomerically forms via N-to-C chirality transmission.



Publication History

Received: 15 August 2025

Accepted after revision: 23 September 2025

Accepted Manuscript online:
23 September 2025

Article published online:
04 November 2025

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