A Practical Synthesis of 5-Substituted 1H-Tetrazoles from Aldoximes Employing the Azide Anion from Diphenyl Phosphorazidate

5-Substituted 1H-tetrazoles were effectively synthesized from aldoximes and diphenyl phosphorazidate (DPPA) under reflux conditions in xylenes. Various aldoximes underwent the cycloaddition reaction to afford the corresponding 5-substituted 1H-tetrazoles in short reaction times and in good yields. Chiral aldoximes derived from amino acids also gave aminotetrazoles with almost no racemization.