Current Organic Chemistry - Volume 24, Issue 6, 2020

Bis(indolyl)methane skeleton is the main building block of many naturally occurring bioactive compounds. Bis(indolyl)methanes are found to possess a wide range of pharmaceuitical efficacies. These important scaffolds are being used as anti-cancer, antioxidant, anti-bacterial, anti-inflammatory, and anti-proliferative agents. In this review, we summarized the latest developments on the synthesis of various bis/tris(indolyl)methane derivatives from the reactions of two equivalents of indoles and one equivalent of aldehydes or indole-3-carbaldehydes under various reaction conditions. More than hundred different catalysts were employed for these transformations which include various metal catalysts, ionic liquids, organocatalysts, surfactants, homogeneous, heterogeneous catalysts etc.

Pyrrole derivatives are nitrogen-containing heterocyclic compounds and widely distributed in a large number of natural and non-natural compounds. These compounds possess a broad spectrum of biological activities such as anti-infammatory, antiviral, antitumor, antifungal, and antibacterial activities. Besides their biological activity, pyrrole derivatives have also been applied in various areas such as dyes, conducting polymers, organic semiconductors. Due to such a wide range of applicability, access to this class of compounds has attracted intensive research interest. Various established synthetic methods such as Paal-Knorr, Huisgen, and Hantzsch have been modified and improved. In addition, numerous novel methods for pyrrole synthesis have been discovered. This review will focus on considerable studies on the synthesis of pyrroles, which date back from 2014.

The need to find alternative sources of energy and environmental protection has resulted in the significant development of organic photovoltaics. The synthesis of organic compounds that will ensure the efficiency of the cells has become a key issue. In this work, we present an overview of materials based on donor-linker-acceptor structural motifs, and summarize the current state of research which can help in the design of new, effective photovoltaic materials.

Industrial wastewater contains abundant organic dyes, antibiotics, pesticides, chemical fertilizers or heavy metal ions, which seriously deteriorate the ecological environment. Among the practical techniques for reducing water pollution, photocatalysis is a kind of sustainable solar energy conversion technique for removing organic contaminants. In this review, the advances in the preparation, modification, and doping of graphitic carbon nitride (g-C3N4), including non-metal doping, metal doping, dual- or tri-doping, are introduced firstly. Then, we systematically reviewed the recent progress of g-C3N4/metal oxide composite photocatalysts, including a g-C3N4/n-type metal oxide, such as TiO2, ZnO, SnO2, WO3, FexOy, CeO2, V2O5, MoO3, MnO2, Nb2O5, In2O3, and a g-C3N4/p-type metal oxide, such as Co3O4, Bi2O3, NiO and Cu2O. At last, we summarized the design principles for preparing heteroatom doped g-C3N4 and g-C3N4/metal oxide composites, and forecast the promising research directions. The main objective is to provide a guideline for designing highperformance heteroatom doped g-C3N4 and g-C3N4/metal oxide photocatalysts.

Chiral allenes are important structural scaffolds found in many natural products and drugs, and in addition, they also serve as building blocks for many organic transformations. The conventional methods for preparing chiral allenes rely on the resolution of racemic allenes and the chirality transfer between non-racemic propargylic derivatives and nucleophilic reagents. In recent years, the synthesis of chiral allenes by asymmetric catalysis has been achieved fruitful results. Among them, enantioselective synthesis of chiral allenes with chiral organic catalysts is particularly prominent. In this paper, the research progress of enantioselective synthesis of chiral allenes catalyzed by chiral organic catalysts in recent years is reviewed, including various reaction systems and synthesis applications.