Alkoxyamine-derived formamidines: configurational control and molecular folding.

N,N'-Disubstituted formamidines, and amidines in general, have very rich configurational, conformational, and tautomeric diversities. As part of an effort to incorporate alkoxyamine-derived formamidine units into foldamers, the first evidence for the isolation of the up-to-now unknown E isomer, the conditions for its exclusive formation, its stability and self-assembly properties, and its configurational isomerization to its much more common Z counterpart are reported. Considering the distinctly different H-bonding patterns displayed by both E and Z isomers, such configurational control may find applications in self-assembly, molecular recognition, and biomimetic systems.