Stereoselective Synthesis of ()-β-Enamido Fluorides from -Fluoroalkyl- and -Sulfonyl-1,2,3-triazoles.

A reaction of -sulfonyl-1,2,3-triazole with boron trifluoride etherate afforded a ()-β-ensulfonylamido fluoride instead of the previously erroneously assigned isomer. The correction of the stereochemistry was based on a ge-1D ROESY NMR experiment and X-ray crystal structure analyses. Application of the reaction to -fluoroalkyl-1,2,3-triazoles afforded new ()-β-enamido fluorides in a stereoselective manner. A mechanism involving coordination of BF with the triazole ring and vinyl diazonium and vinyl cation intermediates was proposed.