Markus Wollenweber

Rigid face-to-face [3.3]-oo′-cyclophanes arene/alkene and arene/arene photocycloaddition reactions

Proximity as origin of unusual photoreactivity is being explored: In the naphtho/ene 5 (X-ray analysis), direct or sensitized photoexcitation induce an efficient meta -addition to the naphthalene nucleus; ortho -(2,3)-addition is not enforced. Naphtho/benzo cyclophane 10 , however, is photochemically “inert”. Structurally related benzo/enes 4 and 17 undergo photoequilibration (2:1) with the respective [6+2]-cycloadducts.

Long-lived [1.1.1.1]- and [2.2.1.1]-‘Isopagodane’ dications: novel 4C/2e σ-bishomoaromatic dications†

The dications generated from [1.1.1.1] and [2.2.1.1]isopagodane in SbF5–SO2ClF solution at –78 °C are of σ-bishomoaromatic nature (4C/2e), very similar in geometry, yet chemically different in their properties.