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In this work, silyl ethers of phenols and alcohols have been successfully prepared and tested as neutral carbon (silicon) centered radical precursors. The organophotocatalyzed oxidation (by the Fukuzumi catalyst) of these ethers caused the cleavage of a C−Si (or a Si−Si) bond for the release of the desired radical to be used for the forging of C(sp3) −C(sp3) (or C(sp3) −Si) bonds via a Giese reaction. [ABSTRACT FROM AUTHOR]

The Michael‐type addition of indoles represents one of the most important C−C bonds forming reactions at their C‐3 position. Herein, we present a mild, versatile and sustainable protocol for the efficient preparation of β‐indolylketones via a Michael addition between indoles and chalcones or α,β‐unsaturated ketones in the presence of substituted arylazo sulfones as photoacid generators (PAGs). [ABSTRACT FROM AUTHOR]

Arylazo sulfones were used as Photoacid Generators (PAGs) for the visible-light photorelease of strong sulfonic acids to promote the ring opening of epoxides in benign media (DMC/water mixtures) or under neat conditions. Water, alcohols, azide and thiocyanate anions, as well as electron-rich aromatics were used in the role of the nucleophile. The resulting 1,2-disubstituted adducts were formed mostly in >99% yield in a high regioselective fashion. [ABSTRACT FROM AUTHOR]

Arylazo sulfonates (Ar−N=N−SO3Na) have been found to undergo photografting on gold surface through both Au−Nsp2− and Au−Csp2− bond formation. The functionalized materials have been fully characterized by infrared reflection absorption spectroscopy (IRRAS), Raman, XPS, DFT calculations and UV‐Vis absorption spectroscopy. These methods permit to evidence aromatic substituents (IRRAS), the Au−N=N signature (Raman and XPS spectroscopy), and the bond dissociation energy values of the two linkages (DFT calculation). The grafting proceeds through two competitive paths, namely a stepwise reaction involving an aryl radical (for the formation of the Au−Ar bonds) and a concerted reaction on the surface of gold (for Au−N=N−Ar bond formation). The occurrence of an aryl radical upon irradiation has been fully evidenced by EPR spectroscopy. Finally, E/Z photoisomerisation of the N=N bonds present on prepared few layer films has been observed by means of UV‐Vis absorption spectroscopy. [ABSTRACT FROM AUTHOR]

An important goal of modern organic chemistry is to develop new catalytic strategies for enantioselective carbon-carbon bond formation that can be used to generate quaternary stereogenic centres. Whereas considerable advances [...]

Ruthenium tris-bipyridine derived complexes functionalized by either carboxyl or phosphonyl groups were tested as sensitizers for the photocatalytic reduction of carbon dioxide in the presence of nickel cyclam acting as a catalyst, and a sacrificial donor. These systems were shown to be as efficient as the unsubstituted compounds in solution. Covalent binding to titania nanoparticles gave slightly different results from those with the untreated semiconductor.

The present review aims to provide an overview of recent developments in photochemical and photocatalyzed synthesis of α‐aryl carbonyls via formation of C(sp)2−C(sp)3 bonds. The approaches described are based on the use of light as the exclusive energy source for the generation of highly reactive carbon radicals, cations or radical ions as the key intermediates of the process. Such strategies efficiently compete with traditional routes, that require the combined use of transition metal complexes, ligands, additives and often harsh reaction conditions. [ABSTRACT FROM AUTHOR]