Emerging concepts in photocatalytic organic synthesis

Abstract

Summary Visible light photocatalysis has become a powerful tool in organic synthesis that uses photons as traceless, sustainable reagents. Most of the activities in the field focus on the development of new reactions via common photoredox cycles, but recently a number of exciting new concepts and strategies entered less charted territories. We survey approaches that enable the use of longer wavelengths and show that the wavelength and intensity of photons are import parameters that enable tuning of the reactivity of a photocatalyst to control or change the selectivity of chemical reactions. In addition, we discuss recent efforts to substitute strong reductants, such as elemental lithium and sodium, by light and technological advances in the field.

The development of luminescent solar concentrator-based photomicroreactors: a cheap reactor enabling efficient solar-powered photochemistry

“…The dye re-emits a down-shifted radiation in every direction. (3) The emitted radiation is guided towards the edge of the material to be collected with a photovoltaic cell…”

“…In other words, how can one maximize the amount of light absorbed by the reaction mixture and thus be productively used for driving chemical transformations? To address this challenge, researchers in synthetic organic chemistry have dramatically increased their efforts over the past years, unlocking the full potential of photochemistry by developing photocatalytic variants which can be used across the entire solar spectrum [3][4][5][6][7][8]. This newly regained interest in the field was further stimulated by the access to low cost, energy efficient, high intensity and durable light sources (e.g.…”

Recent Advances in the Synthesis of Piperazines: Focus on C–H Functionalization

“…In this case, although batch conditions were not directly transposable to flow conditions due to the presence of a precipitate, the replacement of KOH with a soluble base, DBU, allowed for this synthesis to be conducted in flow. In contrast to previous reactions, this method offers a green approach for the synthesis of piperazines through the use of a purely organic photoredox catalyst to promote the radical generation [10,[24][25][26][27][28]. The successful transition of this method from batch to continuous flow conditions offers another advantage over other methods.…”

“…Photoredox catalysis introduces sustainable and greener methods for chemical synthesis. However, due to the potential toxicity and cost associated with transition-metalcatalysts, recent research has been directed towards the use and development of organic photocatalysts [10,[24][25][26][27][28]. Organic photocatalysts offer significantly more sustainability as they can be synthesized from renewable organic materials.…”

“…Organics 2021, 2, FOR PEER REVIEW 8 photocatalysts [10,[24][25][26][27][28]. Organic photocatalysts offer significantly more sustainability as they can be synthesized from renewable organic materials.…”