[3,3]-Sigmatropic Rearrangements of Fluorinated Allyl (Thio)cyanates – A Tool for the Synthesis of Fluorinated (Thio)ureas

Authors

  • Daniel C. Ramb Organisch-Chemisches Institut Münster Westfälische Wilhelms-Universität Münster Corrensstraße 40, 48149 Münster, Germany
  • Lisa Kost Organisch-Chemisches Institut Münster Westfälische Wilhelms-Universität Münster Corrensstraße 40, 48149 Münster, Germany
  • Günter Haufe Organisch-Chemisches Institut Münster Westfälische Wilhelms-Universität Münster Corrensstraße 40, 48149 Münster, Germany. haufe@uni-muenster.de

DOI:

https://doi.org/10.2533/chimia.2014.436

Keywords:

Cyanates, 2-fluorallylic alcohols, Fluorinated ureas and thioureas, Isocyanates, Isothiocyanates, [3,3]-sigmatropic rearrangements, Thiocyanates

Abstract

The first (thio)cyanate to iso(thio)cyanate rearrangements based on 2-fluoroallylic alcohols are presented. Long-chain 2-fluoroallylic alcohols were converted to corresponding N-unsubstituted carbamates by treatment with trichloroacetyl isocyanate. Dehydration using trifluoroacetic anhydride in the presence of triethylamine formed intermediate allylic cyanates, which immediately underwent sigmatropic rearrangement to fluorinated allyl isocyanates. Without isolation the latter delivered fluorinated ureas by addition of amines. The thiocyanate to isothiocyanate rearrangements started from the same fluorinated allylic alcohols, which were first converted to mesylates. Heating in THF with potassium thiocyanate led to fluorinated allyl isothiocyanates, via [3,3]-sigmatropic rearrangement of intermediate allyl thiocyanates. The formed products were further reacted with amines to fluorinated thioureas.

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Published

2014-06-26

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Section

Scientific Articles

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