A reinvestigation of the reaction of allylsilanes with N-phenyltriazolinedione: stereoselective synthesis of substituted urazoles by [3+2] cycloaddition

A stereoselective synthesis of hydroxy substituted urazoles of potential biological significance has been developed via the [3+2] annulation of α-substituted allylic silanes with N-phenyltriazolinedione. The need for complete blocking of the α-CH2 group of allylsilanes for successful [3+2] annulation, as reported previously, is found to be unnecessary.