Template-directed synthesis of helical phenanthroline cyclophanes
A helical home for copper: A sequential, in situ desilylation/dimerization/decomplexation protocol has been used to generate helical enynebridged heterocycles in a copper(I) templated synthesis. Variable temperature 13C NMR analysis of the copper complex (see calculated structure) indicated the barrier to helical isomerization was 13.6 kcalmol-1, an increase of about 4 kcalmol-1 relative to the uncomplexed cyclophane.