Frequency of <i>C</i>-Allylations on Oligoglycinates via <i>N</i>-Ylides

Abstract

The highly selective mono-<i>C</i>-allylation of oligoglycinates such as a diethylenetriaminepentaacetate, an iminodiacetate, and an ethylenediaminetetraacetate via insertion of a vacuum operation between the <i>N</i>-allylation and C-migration steps is reported. It is contrastive that one-pot <i>N</i>-allylation–<i>C</i>-allylation procedure gave a mixture including multiallylated products. In the reaction with <i>N</i>-ylides, <i>gem-C</i>-diallylation and α,α′-<i>C</i>-diallylation of oligoglycinates are strongly inhibited even with the use of an excess of allyl bromide and base. A mechanism to explain this control of the frequency of <i>C</i>-allylation on oligoglycinates via <i>N</i>-ylides is also proposed