In this , we discuss recent syntheses of 5- and 6-membered aromatic heterocycles multicomponent reactions (MCRs) that are catalyzed by group 4-8 transition metals. These MCRs can be categorized based on the substrate components used to generate the cyclized product, as well as on common mechanistic features between the catalyst systems. These particular groupings are intended to highlight mechanistic and strategic similarities between otherwise disparate transition metals and to encourage future work exploring related systems with otherwise-overlooked elements. Importantly, in many cases these early- to mid-transition metal catalysts have been shown to be as effective for heterocycle syntheses as the later (and more commonly implemented) group 9-11 metals.
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http://dx.doi.org/10.1039/d1sc03037j | DOI Listing |
Bioorg Chem
January 2025
Medicinal Chemistry Department, Faculty of Pharmacy, Suez Canal University, Ismailia 41522 Egypt. Electronic address:
Novel 1,2,3-triazole hybrids bearing various substituents have been synthesized as potential anticancer agents. Ligand-based approach has been adopted to design these compounds relying on the hybridization of 1,2,3-triazole with α,β-unsaturated carbonyl, 5- and 6-membered heterocyclic scaffolds. All synthesized members were investigated for their cytotoxic potency against nine types comprising 60 panels of human cancerous cells by the US National Cancer Institute: Development Therapeutic Program (US_NCI_DTP).
View Article and Find Full Text PDFJ Org Chem
January 2025
College of New Materials and Chemical Engineering, Beijing Institute of Petrochemical Technology, Beijing 102617, China.
A facile copper-catalyzed, base-controlled cyclization reaction has been developed for the synthesis of 9-membered cycloalkyne and 6-membered heterocycle sultams under mild conditions. This protocol utilizes a copper-catalyzed intramolecular A (alkyne-aldehyde-amine) coupling reaction to efficiently synthesize 9-membered cycloalkyne sultams in yields up to 90%. Alternatively, by substituting NaHCO with DBU, the protocol achieves selective deprotection of the -propargyl group, thereby facilitating the formation of 6-membered heterocyclic sultams, also in high yields.
View Article and Find Full Text PDFChem Sci
September 2024
Polymer Science & Engineering Department, Conte Center for Polymer Research, University of Massachusetts 120 Governors Drive Amherst Massachusetts 01003 USA
Disulfide-containing polyolefins were synthesized by ring-opening metathesis polymerization (ROMP) of the 6-membered disulfide-containing cyclic olefin, 3,6-dihydro-1,2-dithiine, which was prepared by ring-closing metathesis of diallyl disulfide. This approach facilitated the production of disulfide-containing unsaturated polyolefins as copolymers with disulfide monomer units embedded within a poly(cyclooctene) or poly(norbornene) framework. The incorporation of disulfides into the polymer backbone imparts redox responsiveness and enables polymer degradation chemical reduction or thiol-disulfide exchange.
View Article and Find Full Text PDFChem Soc Rev
November 2024
Department of Chemistry, Ludwig-Maximilians-University München, Butenandtstrasse 5-13, Haus F, 81377 Munich, Germany.
This review highlights the use of functionalized organo-Li, -Mg and -Zn reagents for the construction and selective functionalization of 5- and 6-membered fused bicyclic heteroaromatics. Special attention is given to the discussion of advanced syntheses for the preparation of highly functionalized heteroaromatic scaffolds, including quinolines, naphthyridines, indoles, benzofurans, benzothiophenes, benzoxazoles, benzothiazoles, benzopyrimidines, anthranils, thienothiophenes, purine coumarins, chromones, quinolones and phthalazines and their fused heterocyclic derivatives. The organometallic reagents used for the desired functionalizations of these scaffolds are generally prepared using the following methods: (i) through directed selective metalation reactions (DoM), (ii) by means of halogen/metal exchange reactions, (iii) through oxidative metal insertions (Li, Mg, Zn), and (iv) by transmetalation reactions (organo-Li and Mg transmetalations with ZnCl or ZnO(Piv)).
View Article and Find Full Text PDFAcc Chem Res
October 2024
Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, India.
ConspectusUnlike carbon, boron does not usually form ring compounds due to its electron-deficiency-driven affinity toward polyhedral geometries. The polyhedral boranes having -, -, -, or -shapes can be structurally and electronically correlated using various electron counting rules developed by Wade, Mingos, and one of us. However, in the last few decades, boron chemistry progressed significantly toward ring systems.
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