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Synthesis of Hypervalent Iodonium Alkynyl Triflates for the Application of Generating Cyanocarbenes
Published on: September 8, 2013
A stereoselective thiocyanate conjugate addition to electron deficient alkynes and concomitant cyclization to
Vikas Dwivedi1, Manda Rajesh, Ravi Kumar
1Medicinal & Process Chemistry Division, CSIR-Central Drug Research Institute, BS-10/1, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow 226031, India.
Abstract:
A regio- and stereoselective thiocyanate addition to ynones is achieved using KSCN in AcOH at 70 °C. The reaction is extendable to ynals, ynesulfones, ynoic acids and ynoates. Adducts from ynones were readily transformed into thiazine-2-thione derivatives under slightly modified reaction conditions. In contrast, thiocyanated adducts from ynamides underwent an in situ decyanative amido cyclization towards isothiazolones. None of these events needed any transition metal or catalyst, attaining a high synthetic value.
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