Visible Light-Mediated Decarboxylative Giese Addition Utilizing Thioxanthone or Thioxanthone-TfOH Complex as the Photocatalyst.

Synthetic photochemistry is an alternative, green and sustainable approach in organic synthesis, offering the possibility for the discovery of novel reactivities. Carboxylic acids are abundant and widely used as suitable radical precursors for light-mediated processes, providing access to products that are not accessible via conventional methods. Herein, we report a green, cheap, metal-free, photochemical decarboxylative protocol for the 1,4-radical conjugate addition (Giese reaction) using thioxanthone, a commercially available organic molecule, or a thioxanthone-triflic acid (TfOH) complex, as the photocatalyst, under LED 427 nm irradiation.

Photocatalytic CeCl-Promoted C-H Alkenylation and Alkynylation of Alkanes.

The reemerging field of photoredox catalysis offers numerous advantages towards the development of novel, sustainable and easy-to-execute organic transformations. Herein, we report a light-triggered application of cerium complexes towards the C-H alkenylation and alkynylation of alkanes. An indirect HAT-mediated photocatalytic protocol was developed, using a cerium salt (CeCl ⋅ 7HO) and a chlorine source (TBACl) as the catalytic system.

Deciphering the Knoevenagel condensation: towards a catalyst-free and water-mediated process.

The Knoevenagel condensation constitutes one of the most well-studied and crucial transformations in organic chemistry, since it facilitates the synthesis of numerous valuable compounds. With the advent of green chemistry, several alternative protocols for the Knoevenagel reaction have been introduced and catalyst-free approaches to the Knoevenagel condensation have also been mentioned, however the harsh temperatures employed and the limited substrate scope restricted their application. Herein, we have performed an extensive study on the catalyst-free and water-mediated Knoevenagel reaction, with specific focus on optimising the green parameters and metrics of our methodology.

Light-accelerated "on-water" hydroacylation of dialkyl azodicarboxylates.

The hydroacylation of dialkyl azodicarboxylates has received a lot of attention lately due to the great importance of acyl hydrazides in organic chemistry. Herein, we report an inexpensive and green photochemical approach, where light irradiation (390 nm) significantly accelerates the reaction between dialkyl azodicarboxylates and aldehydes, while water is employed as the solvent. A variety of aromatic and aliphatic aldehydes were converted into their corresponding acyl hydrazides in good to excellent yields in really short reaction times (15-210 min) and the reaction mechanism was also studied.

Cyrene: a bio-based solvent for the Mizoroki-Heck reaction of aryl iodides.

The development of greener and more sustainable methods, as well as the adaptation of already existing protocols to more environmentally friendly procedures, has become crucial for organic synthesis. The introduction and utilization of greener solvents is a very promising alternative, especially when they can replace toxic organic solvents in the known and widely used organic reactions. Cyrene has appeared to be an excellent alternative solvent for a number of organic reactions.