Visible‐Light‐Induced Di‐π‐Methane Rearrangement of Dibenzobarrelene Derivatives

Abstract

It is demonstrated that the di‐π‐methane (DPM) rearrangement of carbonyl‐substituted dibenzobarrelene (9,10‐dihydro‐9,10‐ethenoanthracene) derivatives is induced by visible‐light‐induced triplet photosensitization with Ir(ppy)3, Ir(dFppy)3 or 1‐butyl‐7,8‐dimethoxy‐3‐methylalloxazine as catalysts, whereas derivatives that lack carbonyl substituents are photoinert under these conditions. Notably, the products are formed almost quantitatively.

Photocontrolled Binding of Styrylnaphthyridine Ligands to Abasic Site‐Containing DNA by Reversible [2+2] Cycloaddition and Cycloreversion

“…According to this approach, various photoactive DNA‐binding compounds have been developed, for example, azobenzenes, [14] dithienylethenes, [15] chromenes, [16] spiropyranes, [17] spirooxazines [18] and stilbenes, [19–22] whose photoswitchable DNA‐binding properties are either reversible or irreversible [23] . But surprisingly, there is, to the best of our knowledge, only one example of an application of this concept to AP‐DNA ligands [24] …”

“…[23] But surprisingly, there is, to the best of our knowledge, only one example of an application of this concept to AP-DNA ligands. [24] In order to extend the toolbox of selective AP-DNA ligands we proposed to furnish an established ligand system with a photoswitchable unit, which in turn should allow for an improved selective binding process by means of controlled irradiation. We chose the naphthyridine unit as building block, because derivatives thereof have been shown to be suitable AP-DNA-targeting ligands which bind with reasonable affinity and selectivity to AP sites by hydrogen-bond interactions with the opposing DNA base.…”