In recent years, hydroxylamines derivatives have been exploited as nitrogen-radical precursors in visible-light photochemistry. Their ability to serve as electrophores in redox chemistry has propelled the development of many novel transformations. Fundamental mechanistic aspects as well as the importance in the preparation of nitrogen-containing molecules will be highlighted.

A photoinduced cascade strategy leading to a variety of differentially functionalised nitriles and ketones has been developed. These reactions rely on the oxidative generation of iminyl radicals from simple oximes. Radical transposition by C(sp3)−(sp3) and C(sp3)−H bond cleavage gives access to distal carbon radicals that undergo SH2 functionalisations. These mild, visible‐light‐mediated procedures can be used for remote fluorination, chlorination, and azidation, and were applied to the modification of bioactive and structurally complex molecules.

We report a new family of hexa‐peri‐hexabenzocoronene (HBC)‐based helical nanographenes incorporating π‐extended carbo[5]helicenes bearing an octagonal carbocycle. This family represents a new kind of highly distorted saddle‐helix hybrid nanographenes. For the first time, the eight‐membered ring becomes a constituent of both a carbo[5]helicene and a HBC and thus, the negative curvature is responsible for twisting both units. This novel chiral motif, namely, oct‐[5]helicene results in the largest torsion angle recorded so far for a carbo[5]helicene (θ=79.5°), as it has been suggested by DFT‐calculations and confirmed by X‐ray crystallography. Consequently, the barriers of isomerization become exceptionally high for a [5]helicene unsubstituted in the fjord region since neither racemization nor decomposition were observed at 200 °C for 1 or 3 during 5 h. Therefore, racemic resolutions allowed subsequent chiroptical studies showing the ECD and CPL responses of this novel family of chiral nanographenes.

The selective functionalization of C(sp3)−H bonds at distal positions to functional groups is a challenging task in synthetic chemistry. Reported here is a photoinduced radical cascade strategy for the divergent functionalization of amides and protected amines. The process is based on the oxidative generation of electrophilic amidyl radicals and their subsequent transposition by 1,5‐H‐atom transfer, resulting in remote fluorination, chlorination and, for the first time, thioetherification, cyanation, and alkynylation. The process is tolerant of most common functional groups and delivers useful building blocks that can be further elaborated. The utility of this strategy is demonstrated through the late‐stage functionalization of amino acids and a dipeptide.

In this paper, we have systematically studied how the replacement of a benzene ring by a heterocyclic compound in oligo(phenyleneethynylene) (OPE) derivatives affects the conductance of a molecular wire using the scanning tunneling microscope-based break junction technique. We describe for the first time how OPE derivatives with a central pyrimidine ring can efficiently link to the gold electrode by two pathways presenting two different conductance G values. We have demonstrated that this effect is associated with the presence of two efficient conductive pathways of different length: the conventional end-to-end configuration, and another with one of the electrodes linked directly to the central ring. This represents one of the few examples in which two defined conductive states can be set up in a single molecule without the aid of an external stimulus. Moreover, we have observed that the conductance through the full length of the heterocycle-based OPEs is basically unaffected by the presence of the heterocycle. All these results and the simplicity of the proposed molecules push forward the development of compounds with multiple conductance pathways, which would be a breakthrough in the field of molecular electronics.

Just as “Deconstructivism” appeared as a novel movement in architecture in the 1980s, deconstructive approaches have recently emerged as excellent strategies for scaffold hopping modifications in chemistry. The deconstruction and functionalization of cyclic molecules mainly involves the cleavage of the carbon–carbon (C−C) bond followed by the construction of new bonds. The cleavage of inert C−C single bonds, especially in unstrained cycles, and their subsequent functionalization is still one of the most sought‐after challenges in chemistry. In this vein, radical‐mediated strategies provide an excellent approach for achieving this aim. This minireview is an outline of the history of homolytic cleavage and highlights the recent advances in exploring new chemical space by deconstructive functionalization.

Chiral stapled o-OPEs show excellent circular polarized luminescence responses (glum of 1.1 × 10–2) which can be modulated by carbophilic interactions.

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