Synlett

This study introduces an efficient, environmentally friendly, and sustainable method for synthesizing N-acylhydrazone analogues by engaging isoniazid in a condensation reaction with variously substituted benzaldehydes. The deep-eutectic solvent (ZnCl2/urea) employed in this study acted not only as a solvent but also as a catalyst to facilitate the synthesis of the target compounds within two to six minutes without the requirement of any lengthy purification techniques. The synthetic protocol is operationally simple and offers other remarkable advantages such as a short reaction time, good to excellent yields, a scalable protocol, and a recyclable and reusable catalyst. Additionally, green metrics calculations suggest the present method to be environmentally benign. Finally, the frontier molecular orbitals and the global reactivity parameters of the synthesized compounds were predicted by using density functional theory calculations.

Diaryl diselenides and diaryl ditellurides are commonly employed as selenyl or telluryl sources, and they have a wide range of applications in organic synthesis. Herein, various diaryl diselenides/ditellurides are furnished in moderate to excellent yields under metal-free conditions. This method features high efficiency, good functional group tolerance, straightforward operation, and easy scale-up (running in 4 mmol-scale for most cases). Mechanistic studies indicate that this reaction may proceed via a radical pathway. Significantly, the correct matching of Br– and dimethyl sulfoxide under an air atmosphere is critical to this transformation.

The present article provides a personalized account of our recent work on the synthesis of substituted and fused five-membered heterocycles using various organosulfur building blocks, derived primarily through base-mediated condensation of active methylene compounds with (het)aryl/alkyl dithioesters, which have not been previously explored. We initially describe the ring-opening transformations of 4-[(methylthio)-(het)aryl-methylene]-2-phenyl-5-oxazolones, leading to the synthesis of functionalized oxazoles, thiazoles, and bisoxazoles. We then go on to focus on the synthesis of substituted benzothiophenes, indoles, and benzofurans, as well as their hetero-fused analogs. These compounds are synthesized via transition-metal-catalyzed intramolecular C–heteroatom (C–S, C–N, C–O) bond formation (via cross-coupling or C–H bond functionalization) of various reactive organosulfur intermediates, derived from base-mediated condensation of 2-bromo(het)arylacetonitriles, acetates, or desoxybenzoins or the corresponding 2-unsubstituted precursors. Finally, we highlight the synthetic applications of a new class of previously unexplored organosulfur building blocks, namely, unsymmetrically substituted 1,3-bis(het)aryl-1,3-monothioketones, derived via base-mediated condensation of ketones with (het)aryl/alkyl dithioesters, for the regioselective synthesis of substituted pyrazoles, isoxazoles, thiophenes, imidazoles, and benzothiophenes.1 Introduction2 4-[(Methylthio)-het(aryl)-methylene]-2-phenyl/2-(2-thienyl)-5-oxazolones: Versatile Templates for the Synthesis of Oxazoles, Thiazoles, and Bisoxazoles3 Synthesis of Benzothiophenes, Indoles, and Benzofurans via Transition-Metal-Catalyzed Intramolecular C–Heteroatom Bond Formation4 1,3-Bis(het)arylmonothio-1,3-diketones and 1,3-Bis(Het)aryl-3-(methylthio)-2-propenones: Versatile Intermediates for the Regioselective Synthesis of Five-Membered Heterocycles5 Conclusion

A concise and scalable asymmetric synthesis of (+)-8-epigrosheimin is reported in nine steps using only three column chromatographic purifications with an overall yield 47.0% from (R)-(–)-carvone. Two synthetic routes are evaluated by catalyst-free tandem allylboration–lactonization of two carvone-derived aldehydes and subsequent ene cyclization, where strategy via Lee–Lay aldehyde is found to be more effective for 8-epigrosheimin.

An axially chiral phenanthroline ligand bearing two BINOL units was found to be capable of promoting the copper-catalyzed enantioselective arylation of 2-azonaphthalenes with arylboronic acids. This atroposelective Michael-type addition affords a range of enantioenriched axially chiral biaryl compounds in synthetically useful yields with enantiomeric ratios of up to 91.5:8.5.

The synthesis of bicyclo[3.1.1]heptane (BCHeps) derivatives, which serve as three-dimensional (3D) bioisosteres of benzenes and are the core skeleton of several terpene natural products, is garnering growing interest. The (3+3) cycloadditions of bicyclobutanes (BCBs) represent an attractive method for efficiently accessing (hetero)BCHep skeletons with 100% atom economy. Herein, we give a brief summary of recent achievements in this approach for the synthesis of diverse BCHep derivatives, emphasizing our recent progress in the initial palladium-catalyzed (3+3) cycloadditions of bicyclobutanes with vinyl oxiranes.1 Introduction2 Radical (3+3) Cycloaddition Reaction3 Polar (3+3) Cycloaddition Reaction4 Palladium-Catalyzed Enantioselective (3+3) Cycloaddition Reaction5 Conclusion

An effective strategy for constructing substituted 1-benzyl-1H-1,2,3-triazoles was developed through click reactions of benzylic halides with sodium azide and calcium carbide as sources of nitrogen and acetylene, respectively. The advantages of this method are an easily handled inexpensive source of acetylene, a wide range of substrates, satisfactory yields, and simple workup procedures, which could promote the use of calcium carbide as a sustainable acetylene source in modern industrial chemistry.

The radical/palladium relay catalysis for C–H bond carbonylation is an attractive research topic in synthetic chemistry. It can rapidly prepare carbonylated molecules for synthetic or pharmaceutical applications from highly sought-after feedstocks, such as alkylarenes, alkanes, alkenes, or ethers. The main objective of this Synpacts article is to summarize the development of this research area, mainly focusing on radical/palladium relay catalysis for the carbonylation of single and double C–H bonds.1 Introduction2 Radical/Palladium Relay Catalysis for Single C–H Bond Carbonylation Reaction3 Radical/Palladium Relay Catalysis for Double C–H Bond Carbonylation Reaction4 Conclusions

Synlett 2024; 35: V-DOI: 10.1055/s-0043-1773492Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, GermanyArticle in Thieme eJournals:Table of contents

is a professor at Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, P.R. China. He received his Ph.D. in 2012 from Beijing Institute of Technology (BIT) under the guidance of Prof. Zhiming Zhou. Then, he joined Shanghai Institute of Organic Chemistry to start his academic career. His research interests mainly focus on the design and synthesis of new energetic materials.
Jun Yang received his Ph.D. at Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences in 2005 under the supervision of Prof. Minzhi Deng. He is now a professor of the Shanghai Institute of Organic Chemistry, CAS. His research interests primarily include the synthesis of energetic materials and energy regulation materials for solid and liquid propellants.