[reaction: see text] The in situ preparation of a sulfonium ylide reagent achieved the highly diastereoselective epoxidation of isatins, so that a new and straightforward access to biologically significant spiro-epoxyoxindoles is provided. The first investigations of an asymmetric version are reported with enantiopure sulfides.
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http://dx.doi.org/10.1021/ol070439x | DOI Listing |
Org Lett
January 2025
Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur 721302, India.
A straightforward synthesis of -dihydronaphthodioxine has been efficiently accomplished through Cu(II)-NHC catalysis, involving the stereoselective ring opening of -epoxides with quinoid-carbene. Intramolecular S2-like substitution facilitates the inversion of stereochemistry during -epoxide ring opening. This reaction has been developed under simple conditions, demonstrating a broad substrate scope with a wide chemoselective profile.
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January 2025
School of Chemistry and Chemical Engineering, Hunan University of Science and Technology, Xiangtan, Hunan 411201, China.
An unprecedented synergistic copper- and amine-catalyzed cyclization of enynone is reported. This reaction features an efficient and straightforward construction of multisubstituted tetralone through an amine-assisted regioselective oxygen atom transfer process and stereoselective intramolecular Michael addition cyclization. Under dehydrative reaction conditions, the synthesis of tetrahydronaphthylimine derivatives with ketone group tolerance is achieved, which could be challenging via traditional methods.
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January 2025
Department of Natural Sciences, The Open University of Israel, Ra'anana 4353701, Israel.
The development of new protocols for stereospecific and stereoselective halogenation transformations by mild reaction conditions is a highly desirable research target for the chemical and pharmaceutical industries. Following the straightforward methodology for directly transforming a wide scope of alcohols to alkyl bromides and chlorides using substoichiometric amounts of thioureas and N-halo succinimides (NXS) as a halogen source in a single step, we noticed that in apolar solvents bromination of chiral secondary alcohols did not produce the expected racemates. In this study, the stereochemical aspects of the bromination reaction were examined.
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January 2025
Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry and Sichuan Province, Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University, Chengdu 610041, China.
Kdn is a common member of the sialic acid family. Carbohydrates containing Kdn residues are widely distributed in nature and embody important biological information. However, the methods for synthesizing Kdn glycosides are limited, which restricts their biological study.
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December 2024
CNRS, INSA Rouen Normandie, Univ Rouen Normandie, Normandie Univ, COBRA UMR (6014), F-76000 Rouen, France.
1,3-Dienes are versatile raw materials for building molecular complexity. We report herein mild conditions for the regio- and stereoselective [only the () isomer obtained] 1,4-carboalkoxylation of 1,3-dienes. This electrochemical multicomponent reaction provides an eco-efficient and straightforward access to a diverse range of ()-polyfunctionalized allyl ether products, without requiring any metal catalyst.
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