Two suitably protected building blocks (11 and 33) for the preparation
of amide-linked heptaglucoside mimetic 2, an analogue of the naturall
y occurring phytoalexin elicitor 1a, were readily accessible by glycal
chemistry. Sequential elongation of terminal glucuronide 21 with lami
naribiosyl hemiaminal 33 and anomeric amine 11 by EDC/HOBt-catalyzed c
ondensation and two-step conversion of the C6-OTr moiety into the corr
esponding carboxylate function afforded homogeneous carbopeptoid 2 in
high overall yield. It was found that replacement of the acetal linkag
es by the more rigid amide bonds destroys the phytoalexin-elicitor act
ivity.