The Base-Induced Fragmentation of N,N-Dibenzyl-N′-aryltriazenes

Abstract

Deprotonation of N,N-dibenzyl-N'-aryltriazenes, either in liquid phase or on solid support, by a strong base (n-BuLi or LDA) leads to fragmentation of the N-N single bond to give an imine and a diazenyl anion, which decomposes by loss of nitrogen to the parent aryl anion. The imine is deprotonated to give a 2-aza allyl anion, which is subsequently trapped by electrophiles. As an overall result, this fragmentation of the T1 triazene anchoring group represents a new traceless cleavage mode of this linker. The same mode of fragmentation was observed for the T2 linker leading to 2-aza allyl anions in liquid phase. The dibenzylamino moiety is apparently crucial since pyrrolidinodiazenylarenes can be metallated at the heterocycle without cleavage.