Regiodivergent Organocatalytic Reactions

Abstract

Organocatalysts are abundantly used for various transformations, particularly to obtain highly enantio- and diastereomeric pure products by controlling the stereochemistry. These applications of organocatalysts have been the topic of several reviews. Organocatalysts have emerged as one of the very essential areas of research due to their mild reaction conditions, cost-effective nature, non-toxicity, and environmentally benign approach that obviates the need for transition metal catalysts and other toxic reagents. Various types of organocatalysts including amine catalysts, Brønsted acids, and Lewis bases such as N-heterocyclic carbene (NHC) catalysts, cinchona alkaloids, 4-dimethylaminopyridine (DMAP), and hydrogen bond-donating catalysts, have gained renewed interest because of their regioselectivity. In this review, we present recent advances in regiodivergent reactions that are governed by organocatalysts. Additionally, we briefly discuss the reaction pathways of achieving regiodivergent products by changes in conditions such as solvents, additives, or the temperature.

Regiodivergent Nucleophilic Fluorination under Hydrogen Bonding Catalysis: A Computational and Experimental Study

“…The development and widespread application of asymmetric organocatalysis was recognized with the Nobel Prize in Chemistry awarded in 2021 to List and MacMillan . Organocatalysts were also deployed to control regioselectivity including examples of asymmetric regiodivergent reactions . Standout examples are the development of the regiocontrolled N -alkylation of triazoles with an amidinium hydrogen-bond donor (HBD) catalyst and an asymmetric regiodivergent cycloaddition catalyzed by an N -heterocyclic carbene leading to regioisomeric dihydroisoquinolines …”

Catalyst-controlled regiodivergent Friedel–Crafts reactions of 1-naphthols with 2,3-dioxopyrrolidines: synthesis of polycyclic 2-pyrrolidinones

“…3 A regiodivergent reaction, which enables two or more regioisomeric products to be synthesized from the same starting materials, has been a hot topic at the frontier of organic synthesis. 4 These reactions can be controlled by the choice of catalysts or modification of reaction conditions. 5–9 Hence, the development of efficient synthetic methodologies for regiodivergent reactions is still in high demand.…”

Regioselectivity Switch between Enantioselective 1,2- and 1,4-Addition of Allyl Aryl Ketones with 2,3-Dioxopyrrolidines

“…Despite progress, achieving switchable regioselectivity of substrates with multiple reaction sites remains challenging, especially when aiming to produce complex structures from identical starting materials. , The regioselective switch of sites’ reactions has been achieved mainly by various reaction conditions such as catalysts, additives, solvents, temperatures, and ligands. − Hence, to pursue the goal of developing efficient synthetic methodologies for regiodivergent reactions is still highly in demand.…”