Synlett

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.

A novel strategy has been developed for the direct and regioselective ortho-acetoxylation of N-(2-benzoylphenyl)benzamides through C–H activation using a catalytic amount of Pd(OAc)2 (5 mol%) and a stoichiometric amount of PhI(OAc)2 in a mixture of acetic anhydride and acetic acid. By using this protocol, a new series of niclosamide derivatives was produced in good yields. This is the first report on the synthesis of niclosamide and its derivatives by means of C–H functionalization. This newly developed method offers several advantages such as high regioselectivity, operational simplicity, and good to excellent yields. It provides a short three-step process for the synthesis of niclosamide involving acid–amine coupling, ortho-acetoxylation through C–H activation, and deacylation.

Indolo[2,1-b]quinazolin-12(6H)-one derivatives are prevalent in many synthetic intermediates, pharmaceuticals, and organic materials. Herein, we developed a photoredox radical cascade cyclization reaction that uses visible light as the primary energy input to promote the reaction, leading to a series of indolo[2,1-b]quinazolin-12(6H)-one derivatives under oxygen conditions.

A practical method for the debenzylation of aryl benzyl ethers has been developed using easy-to-operate I2 and Et3SiH, as well as the green solvent ethyl acetate. Halo, methoxy, ester, and nitro groups on the benzene ring of the aryl benzyl ether are compatible with this debenzylation. Control experiments revealed that Et3SiI, generated in situ, might be the actual promoter of the procedure. This method does not require a separate desilylation reaction to obtain phenol products.