“…The core structure 1,3,5-triazin-2(1 H )-one, which was previously evaluated in our study on acid-catalyzed benzylating reagents, achieved the compatibility between the reactivity and stability of 1 . On the basis of our previous findings, the substituents of 1 (the tert -butyl and N -propargyl groups) were rationally designed to suppress an N -alkylating side reaction that was occasionally observed in the reaction of triazine-based alkylating reagents. ,− The sterically bulky tert -butyl group on the triazine ring effectively reduced the N -benzylating side reaction caused by benzyl cation species . In addition, the fixation of the heterocyclic core structure through the introduction of the N -substituent inhibited the side reaction that occurred via core structure isomerization during acid-catalyzed O -benzylation .…”