Current Organic Chemistry - Volume 29, Issue 19, 2025

Naturally occurring coumarin compounds with the typical benzopyrone framework are found in remarkable concentrations in plants. Moreover, they have also been found in animals, microbes, and other sources. The versatility of the coumarin scaffold extends beyond medicinal chemistry, with applications in agrochemistry, cosmetics, and fragrances. However, this review focuses on the diverse biological activities of metal-complexed coumarin derivatives, including their roles as antimicrobial, anticancer, antioxidant, antidiabetic, anticholinesterase, and antipancreatic cholesterol esterase agents. Notably, the antimicrobial and anticancer properties of these complexes have received significant attention in current research, demonstrating the most promising and impactful results. Coumarin-containing metal complexes have been widely studied in recent years as a growing area of medicinal chemistry in pharmaceutical science. Hence, there is a wide range of potential research topics due to the modifying ability of various ligands, such as N-heterocyclic coumarins, being developed into a metal complex. This has been an innovative strategy in recent years. Therefore, this review article aims to have a concise account and a detailed highlight of the individually associated schematic strategies used in synthesis (carried out through conventional, synthetic, microwave-assisted, and green approaches), along with the characterization of the compounds pertaining with the significant biological activities, which are assessed by suitable evaluating methods.

Carbazoloquinones possess a unique structural characteristic commonly found in natural compounds. Precisely, these molecules have been integral to traditional medicine, addressing various health concerns such as malaria, cancer, and neuronal protection. This review centers on the occurrence, biological activity, and asymmetric synthesis of bioactive carbazole-3,4-quinone alkaloids, which demonstrate notable properties like neuronal cell protection and free radical scavenging. To date, this is the first exclusive review focusing on carbazole-3,4-quinones. We delve into the asymmetric and enantioselective synthetic methods used to synthesise three families of naturally occurring carbazole-3,4-quinone molecules: carbazoquinocins, (±)-carquinostatins, and (±)-lavanduquinocins. Despite the existence of efficient synthetic strategies for some of these compounds, there remain challenges and opportunities for developing new methods for carbazole-3,4-quinone natural products.

Aluminum is the most abundant metal in the Earth’s crust and is the principal constituent of many common minerals. Taking advantage of its higher abundance and lower costs and toxicity compared with more traditional transition metals, this main group metal has emerged as a green metal of high potential and utility in organic synthesis. While many racemic aluminum catalysts have been early applied as Lewis acids to promote various reactions, such as Friedel-Crafts acylations, Alder-ene reactions, and polymerizations, chiral aluminum counterparts have been developed only since the 1990s in asymmetric catalysis. Indeed, the possibility of tuning the Lewis acidity of aluminum by making use of appropriate chiral ligands allows to control the stereoselectivity in a wide diversity of catalytic enantioselective reactions. For example, various types of ligands have been chelated to aluminum, such as salens, BINOL, and VANOL derivatives, TADDOL-derived ligands, cinchona alkaloids, and N,N’-dioxides. In the last decade, a wide variety of highly enantioselective aluminum-catalyzed transformations have been developed, spanning from basic reactions, such as cyanations of carbonyl compounds, aldol reactions, reductions, cycloadditions, cyclizations, α-alkylations of aldehydes, Michael additions, acyloin rearrangements, copolymerization etc., to more challenging and modern processes, such as domino and tandem reactions. The goal of this review is to collect the recent developments in enantioselective aluminum-catalyzed reactions of all types published since the beginning of 2015. It shows that asymmetric aluminum catalysis, which suits the growing demand for greener processes, offers a real opportunity to replace toxic and expensive metals soon.

Terpenes and terpenoids, which are a large and diverse class of organic compounds, are widely distributed in many plants. In recent years, there has been a growing interest in the biosynthesis and biological activity of terpenes and terpenoids in order to fully exploit their efficacy in a wider range of applications, such as medicine, biology, flavors and fragrances, food, and cosmetics. This review aims to update and elucidate the classification, pharmacology, and production of terpenes and terpenoids, focusing on the bioactivities and biosynthetic mechanisms. Their classification methods, production routes, and potential application ranges are discussed in detail. Moreover, the research on terpenes and terpenoids since 2014 is also reviewed by identifying the trends and keywords through bibliometric analysis, classifying terpenes and terpenoids in recent studies according to their chemical structure, and summarizing their production methods and pharmacological properties. Generally, terpenes and terpenoids can be divided into five categories based on the number of isoprene units, but are highly diverse in structure. Terpenes and terpenoids exhibit various bioactivities, including anti-inflammatory, antibacterial, anticancer, and antioxidant effects, due to their structural diversity. The common production methods mainly include extraction and separation, chemical synthesis, and biosynthesis. Different approaches to biosynthesis have been proposed but have not been applied in large-scale production. With increasing medicinal potentials, the demand for terpenes and terpenoids will continue to increase, where biosynthesis will play a key role in improving their production.