10.1016/j.jfluchem.2020.109516
The research focuses on the development of a general methodology for the trifluoromethylation of 1-aryl-4-iodo-1,2,3-triazoles using methyl-2,2-difluoro-2-(fluorosulfonyl) acetate (MDFA) and copper (I) iodide, promoted by tetrabutylammonium iodide (TBAI). The study explores the synthesis of 1-aryl-4-trifluoromethyl-1,2,3-triazoles, which are important due to the unique properties of the 1,2,3-triazole ring and the significance of the trifluoromethyl group in pharmaceuticals and agrochemicals. The experiments involved the optimization of reaction conditions, including the evaluation of different solvents, copper sources, and additives, with a particular emphasis on the role of TBAI in enhancing conversion rates. The analyses used to monitor the progress and outcomes of the reactions included liquid chromatography-mass spectrometry (LCMS), high-performance liquid chromatography (HPLC), nuclear magnetic resonance (NMR) spectroscopy, and high-resolution mass spectrometry (HRMS). These techniques were crucial for characterizing the intermediates and final products, as well as for optimizing the reaction conditions to achieve the desired trifluoromethylated heterocycles with broad functional group tolerance and on a multi-gram scale.
10.1016/S0040-4039(00)81514-2
The research focuses on the synthesis of specifically deuterated 1,3-diethoxy-carbonylallylidene-triphenylphosphonium ylides. The purpose was to develop methods for introducing deuterium labels in the ?- and ?-positions of the allylidene-phosphonium ylide without deuterium scrambling. In the research, ethyl propynoate serves as a key starting material for the synthesis of deuterated compounds. It is used in the Michael addition reaction to produce the ?-deuterated phosphonium ylide and also as a reactant in the synthesis of ethyl 3-deuteriopropynoate, which is crucial for the ?-deuteration process. Deuterium oxide (D2O) plays a vital role in the deuterium exchange reactions. It is used to introduce deuterium atoms into the molecules, specifically in the synthesis of ethyl 3-deuteriopropynoate and in the acid-catalyzed deuterium exchange to produce the ?-deuterated phosphonium ylide. Sodium deuteroxide (NaOD) acts as a base in the deuterium exchange process. It is used to facilitate the deuterium exchange reactions and to neutralize any acid present, ensuring that the deuterium atoms are retained in the final products. Tetrabutylammonium iodide (TBAI) functions as a phase-transfer catalyst. It helps to transfer reactants between the organic and aqueous phases, enhancing the efficiency of the deuterium exchange reactions in the synthesis of ethyl 3-deuteriopropynoate. For ?-deuteration, ethyl propynoate was treated with deuterium oxide under phase transfer conditions to synthesize ethyl 3-deuteriopropynoate, which was then reacted with the ylide to produce the ?-deuterated phosphonium ylide. For ?-deuteration, the ylide was subjected to acid-catalyzed, regiospecific deuterium exchange with deuterium oxide and deuterium chloride, followed by base treatment to avoid deuterium loss. The methods resulted in high deuterium incorporation (>90%) and good yields (66-80%), providing a reliable way to introduce deuterium labels for further studies.
10.1021/jo010703e
The study describes a practical synthesis of a second-generation benzoin photolabile safety-catch (BPSC) linker for solid-phase organic synthesis (SPOS). The new linker, featuring a carboxylic acid functionality for resin attachment and a four-carbon tether for enhanced stability, can be loaded onto amine-terminating resins or preloaded with substrates in solution before resin immobilization. This approach offers improved control over linker loading and substrate attachment, making it versatile for SPOS applications. The research highlights the synthesis process, resin attachment, and photolytic cleavage efficiency, demonstrating the linker's potential utility in complex organic synthesis.
10.1055/s-0029-1218711
The study presents an efficient one-pot synthesis method for oxime ethers from alcohols using triphenylphosphine and carbon tetrachloride. The process involves the O-alkylation of oximes with various structurally diverse alcohols in the presence of catalytic amounts of tetrabutylammonium iodide and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) in refluxing acetonitrile. The chemicals serve specific roles: triphenylphosphine and carbon tetrachloride convert alcohols into alkyl halides, DBU acts as a base to activate the O-H bond in oximes, and tetrabutylammonium iodide functions as a phase-transfer catalyst. The synthesized oxime ethers are important in organic and medicinal chemistry, used for introducing functional groups into organic compounds and as key structural motifs in drugs. The study demonstrates high efficiency and selectivity, with primary alcohols being more reactive than secondary alcohols in O-alkylation, and the method predominantly yields O-alkyl ethers over nitrones. The study also includes semiempirical quantum-mechanic calculations to support the stability of the synthesized products, indicating a lower heat of formation for Z-isomers.
10.1021/jo9712714
The research focuses on the enantioselective synthesis of α-dibenzylamino alcohols, which are key precursors to synthetically important R-amino aldehydes, also known as Reetz aldehydes. These compounds are valuable due to their stability and high diastereoselectivity in reactions with organometallics. The study presents a dynamic kinetic resolution process for the preparation of these alcohols from racemic α-halo acids, using (R)pantolactone esters and primary amines, including dibenzylamine, in the presence of tetra-n-butylammonium iodide. The process yields (S,R)-R-amino esters with good to excellent de's (77-98%) and acceptable yields (60-85%). The resulting esters are then reduced with LiAlH4 to give enantiomerically enriched α-dibenzylamino alcohols without loss of stereochemical integrity. The study also explores the use of tert-butyl (4S)1-methyl-2-oxoimidazolidine-4-carboxylate as a chiral auxiliary, which was found to be superior to (R)-pantolactone in the dynamic kinetic resolution process. The research concludes that these auxiliaries can provide a variety of α-dibenzylamino alcohols and the derived Reetz aldehydes in either enantiomeric form, offering an efficient route to these compounds.
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