Stereospecific synthesis of 1,5-disubstituted tetrazoles from ketoximes via a Beckmann rearrangement facilitated by diphenyl phosphorazidate

A novel method for the stereospecific synthesis of 1,5-disubstituted tetrazoles from ketoximes via the Beckmann rearrangement was developed using diphenyl phosphorazidate (DPPA) as both the oxime activator and azide source. Various ketoximes were transformed into the corresponding 1,5-disubstituted tetrazoles with exclusive trans-group migration and no E-Z isomerization of the ketoxime. This method enables the preparation of 1,5-disubstituted tetrazoles without using toxic or explosive azidation reagents. (C) 2019 Elsevier Ltd. All rights reserved.