Incorporation of a molecular hinge into molecular tweezers by using tandem cycloadditions onto 5,6-dimethylenenorbornene.
Site-selective 1,3-dipolar coupling at the norbornene pi-bond of 5,6-dimethylenenorbornene 1 yields cycloadducts with an end-fused 1,3-diene system which have been reacted with N=N (or C=C) dienophiles to produce ribbon molecules, in which the internal diazacyclohexene (or cyclohexene) subunits are capable of acting as conformational hinges. Direct coupling of 5,6-dimethylenenorbornene with 1,3,4-oxadiazoles or dual coupling with bis(cyclobutene epoxides) afforded bis(1,3-dienes) that diastereoselectively react with dienophiles to produce new, conformationally mobile, molecular tweezers.
Warrener
R N
RN
Centre for Molecular Architecture, Central Queensland University, Australia. r.warrener@cqu.edu.au
Butler
D N
DN
Liu
L
L
Margetic
D
D
Russell
R A
RA