An evidence of contact ion pair in β-(acyloxy)alkyl radical heterolysis during copper(I)-mediated synthesis of trisubstituted alkenes
2014
Ram, Ram N. | Tittal, Ram K.
The first evidence for a unified mechanism of heterolysis in β-(acyloxy)alkyl radical involving contact ion pair (CIP) is presented for both fragmentation and rearrangement of the acyloxy group in the reaction of 1-alkoxy-2,2,2-trichloroethyl acetate with 2molequiv each of CuCl and bpy in refluxing DCE under a N2 atmosphere and availed this reaction for the synthesis of Z-stereoselective trisubstituted alkenes. The stereochemistry of the trisubstituted alkenes was assigned by the uniform pattern of the chemical shift values of some relevant signals in ¹H and ¹³C NMR spectra. This assignment was further supported by the X-ray diffraction spectroscopy of Z-1-chloro-2-(4-nitrobenzyloxy)vinyl acetates.
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