The combination of 2-NsNH 2/NCS and MeCN as the nitrogen sources for the regio- and stereoselective formation of imidazolines from α,β-unsaturated ketones

Cody Timmons, Dianjun Chen, C. Elizabeth Barney, Sameer Kirtane, Guigen Li

Research output: Contribution to journalArticle

12 Scopus citations

Abstract

A new nitrogen source combination was found for the regio- and stereoselective diamination of α,β-unsaturated ketones. This combination employs the readily available and inexpensive combination of NCS and 2-NsNH 2 as the electrophilic nitrogen source, and acetonitrile as the nucleophilic nitrogen source, respectively. The reaction is easily performed by mixing olefin, 2-NsNH 2, NCS and 4 Å molecular sieves in freshly distilled acetonitrile at room temperature. The reaction is chemoselective without the formation of any haloamine side products. A new aziridinium ion formed from enones and 2-NsNHCl is suggested to exist and to react with nitrile via a [2+3] cycloaddition mechanism, which is responsible for the excellent regio-, stereoselectivity of the resulting diamination products. The regio-, stereo- and chemoselective imidazolination of enones has been established by using the new combination of 2-NsNH 2/NCS as the electrophilic nitrogen source and MeCN as the nucleophile. The reaction is very convenient to carry out simply by mixing olefin, 2-NsNH 2, NCS and 4 Å molecular sieves in freshly distilled acetonitrile at room temperature. The aziridinium ion formed from the reaction of 2-NsNCl with olefins and the corresponding [2+3] cycloaddition are proposed during the reaction process to control regio- and stereoselectivity.

Original languageEnglish
Pages (from-to)12095-12099
Number of pages5
JournalTetrahedron
Volume60
Issue number52
DOIs
StatePublished - Dec 20 2004

Keywords

  • Diamination
  • Diamine
  • N,N-Dichloro-2-nitrobenzenesulfonamide
  • NCS

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