Thermochromism in Molecular Tweezers

Significance

The authors describe the synthesis of a variety of substituted dibenzocyclooctatetra-ene scaffolds. The synthesis starts with a Sonogashira coupling followed by a palladium-mediated partial hydrogenation to the cis-olefin which is subsequently cyclized using NaCN followed by DBU. Further derivatization is carried out by reduction to the aldehyde followed by installation of the methoxymethyl group. This linear sequence allows the authors to readily derivatize the dibenzocyclooctatetraene scaffold. The resulting molecules readily isomerize between the syn and anti forms behaving as dynamic molecular tweezers. Introduction of a guest molecule shifts the equilibrium to the syn isomer.