Mild Preparation of Functionalized [2.2]Paracyclophanes via the Pummerer Rearrangement

[2.2]Paracyclophanes, incorporating functional groups in
the aliphatic bridges, suitable for elimination to give
[2.2]paracyclophanedienes, are synthesized through a novel
approach. It relies on a double Pummerer rearrangement on
dithiacyclophane precursors, followed by ring contraction
through a photochemical sulfur extrusion, and it is compatible
with aryl moieties possessing very different electronic
properties.