Refernces
10.1055/s-2004-820052
The study presents a solid-phase synthesis method for indol-2-ones, a pharmacophore found in various drugs and alkaloids, using aryl radical cyclization of resin-bound N-(2-bromophenyl)acrylamides. Key chemicals include commercially available 2-bromoanilines, acryloyl chloride derivatives, and Bu3SnH (tri-n-butyltin hydride) as a reducing agent. The solvent DMF (dimethylformamide) was identified as optimal for the radical cyclization, enhancing the reagent concentration effect on the polymer support. The study leverages microwave irradiation to accelerate the reaction, significantly reducing the time compared to conventional thermal heating. The synthesized indol-2-ones were obtained in good yields and high purity, demonstrating the efficiency of the method for combinatorial chemistry and solid-phase synthesis.
10.1021/jo0492416
The study presents a novel protocol for the stereoselective synthesis of C1-C8 and C15-C21 subunits of (+)-discodermolide, a potent anti-cancer agent, through diastereoselective dihydroxylation and regioselective deoxygenation of dihydropyranones. Key chemicals used include R-pinene-based chiral "allyl"-borane reagents for introducing initial chirality, Grubbs's second-generation ruthenium catalyst for ring-closing metathesis reactions, OsO4/NMO for dihydroxylation, phenylchlorothionoformate and tributyltin hydride for regioselective deoxygenation, and various protecting groups and reagents for functional group transformations. These chemicals served the purpose of constructing the complex molecular structures of the subunits with high stereochemical control, which is crucial for their potential application in cancer treatment therapies.
10.1021/jo500465m
The research focuses on the development of a simple, efficient, and practical method for the synthesis of C-2 deoxy-2-iodo glycoconjugates using hypervalent iodine-mediated reactions within self-assembled structures. The purpose of this study was to explore regioselective iodination of glycals through surfactant-assembled structures, utilizing cetylammonium bromide (CTAB) and polycoordinated iodine reagents, to synthesize 2-deoxy-2-iodo acetates. The conclusions drawn from the research indicate that a fully stereoselective method for the synthesis of 2-deoxy-2-iodo glycosides has been successfully identified. The process involved the use of various chemicals, including PhI(OCOR)2, per-O-acetyl glucal, and CTAB, as well as other reagents such as Bu3SnH/AIBN for radical deiodination, and TMSOTf for intramolecular glycosidation. The study also successfully synthesized a range of 2-iodo glycosyl esters and demonstrated the potential for the synthesis of glycopolypeptides and other materials using the 2-deoxy serinyl glycosides obtained from the process.
10.1016/S0040-4039(00)87637-6
The research aimed to investigate the stereochemistry of the reduction of gem-dibromo and monobromocyclopropanes using lithium aluminum hydride (LAH), sodium bis(2-methoxyethoxy)aluminum hydride (SMEAH), and tributyltin hydride (TBTH). The purpose was to understand the reaction mechanisms and intermediates involved in these reductions, particularly focusing on the role of cyclopropyl radicals. The study concluded that the reductions proceed through configurationally equilibrated cyclopropyl radicals as intermediates, with LAH and TBTH reductions showing similar results, while SMEAH reductions suggested an anion mechanism. The research also provided evidence for the nature of the product-forming step in these reductions and tested for deuterium incorporation through the work-up media, which supported the proposed mechanisms. The chemicals used in the process included the cyclopropanes themselves, LAH, SMEAH, TBTH, and various solvents and reagents for the reduction and work-up steps.
10.1002/ejoc.200500907
The research focuses on the radical addition reactions of phosphorus hydrides, aiming to develop synthetic radical reactions as non-metal hydride alternatives to toxic metal hydrides, particularly tributyltin hydride. The study investigates how the reactivity of phosphorus hydrides is influenced by substituents on phosphorus and how this affects the efficiency of radical additions. The researchers found that phosphorus hydrides with particularly weak P-H bonds undergo radical additions more readily, a phenomenon explained by calculated bond dissociation energies. The study also explored the use of microwaves to initiate radical additions, which resulted in shorter reaction times and higher yields compared to conventional heating or initiators. Furthermore, the article discusses the reactivity of organophosphorus adducts in Horner–Wadsworth–Emmons-type (HWE) reactions. Chemicals used in the process include various phosphorus hydrides such as diethyl phosphite, diethyl thiophosphite, hypophosphorous acid, and their derivatives, along with organohalides and xanthates as substrates for the reactions.
10.1016/j.tet.2007.03.017
The research explores a novel method for radical cyclizations of hydrazones using a silicon-tethered 1-bromovinyl group as a radical precursor. The purpose is to develop an effective strategy for synthesizing chiral a-branched amines through intramolecular radical additions, expanding the versatility of silicon-tethered radical cyclizations. Tributyltin hydride (Bu?SnH) is a powerful reducing agent commonly used in organic synthesis to generate radicals. In this study, Bu?SnH serves as the radical initiator, providing the necessary hydrogen radical to initiate the radical cyclization process. Azobisisobutyronitrile (AIBN) is a widely used radical initiator in organic chemistry. It decomposes thermally to produce nitrogen gas and a pair of isobutyronitrile radicals. In this research, AIBN is used in conjunction with Bu?SnH to facilitate the generation of radicals. The study concludes that the silicon-tethered 1-bromovinyl group significantly enhances reactivity, allowing for efficient cyclizations with moderate to good yields. However, the 6-exo cyclizations were found to be non-selective and limited in scope due to issues with β-elimination. The research demonstrates a rational approach to enhancing reactivity in silicon-tethered cyclizations and highlights the potential for further developments in this area.
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