An efficient synthesis of a low molecular weight, chiral nonracemic and C(2)-symmetric bipyridyl ligand is reported. The ligand was prepared using a catalytic asymmetric dihydroxylation reaction of a pyrindine as a key step. The ligand was evaluated in the asymmetric copper(I)-catalyzed cyclopropanation reactions of a series of alkenes and diazoesters. Very high diastereoselectivities and enantioselectivities were observed (>95:5 dr and up to 99% ee). These are the highest reported stereoselectivities for a chiral bipyridyl ligand. [structure: see text]
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Plants (Basel)
December 2024
Departamento de Química, Universidad Técnica Particular de Loja (UTPL), Calle Paris s/n y Praga, Loja 110107, Ecuador.
This study presents the first chemical and enantioselective analyses of essential oils (EOs) derived from the leaves of two endemic species, Cuatrec. and (Kunth) Cass., from Loja, Ecuador.
View Article and Find Full Text PDFJ Am Chem Soc
December 2024
Institute for Organic Chemistry, University of Regensburg, 93053 Regensburg, Germany.
Diarylmethanes play, in part, a pivotal role in the design of highly potent, chiral, nonracemic drugs whose bioactivity is typically affected by the substitution pattern of their arene units. In this context, certain arenes such as -substituted benzenes or unsubstituted heteroarenes cause particular synthetic challenges, since such isosteric residues at the central methane carbon atom are typically indistinguishable for a chiral catalyst. Hence, the stereoselective incorporation of isosteric (hetero)arenes into chiral methane scaffolds requires the use of stoichiometrically differentiated building blocks, which is typically realized through preceding redox-modifying operations such as metalation or halogenation and thus associated with disadvantageous step- and redox-economic traits.
View Article and Find Full Text PDFJ Am Chem Soc
November 2024
Frontiers Science Center for Transformative Molecules, School of Chemistry and Chemical Engineering, Zhangjiang Institute for Advanced Study, Shanghai Jiao Tong University, Shanghai 200240, China.
Nucleoside analogues have seen significant advancements in treating viral infections and cancer through ProTide technology, leading to a series of FDA-approved drugs such as sofosbuvir, tenofovir alafenamide, and remdesivir. The stereochemical configuration at the phosphorus center of ProTides significantly influences their pharmacological properties, necessitating efficient stereoselective synthesis. Traditional methods using chiral auxiliaries or nonracemic phosphorylating agents are labor-intensive and inefficient, while recent organocatalytic approaches, despite their promise, still face limitations.
View Article and Find Full Text PDFJ Org Chem
November 2024
Dipartimento di Scienze Fisiche e Chimiche, Università degli Studi dell'Aquila, Via Vetoio, 67100 Coppito, AQ, Italy.
The distinctive features of gold self-relay catalysts were alternatively utilized in the intriguing cascade condensation of 2-aminobenzaldehydes with alcohols and amines. Using NaAuCl·2HO as a catalyst, a range of 13-alkyloxy-7,11-dihydro-6,13-6,12-[1,2]benzenoquinazolino[3,4-]quinazoline derivatives was produced in good to high yields through AB condensation of various 2-aminobenzaldehydes with alcohols. By carefully choosing the reaction conditions, gold catalysis also proved effective for AB condensation with primary aryl- and benzylamines, facilitating the synthesis of challenging McGeachin bisaminals, including a chiral nonracemic derivative of 2-()-methylbenzylamine.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
October 2024
Department of Chemistry, Tokyo Institute of Technology present name, Institute of Science Tokyo, 2-12-1 O-okayama, Meguro-ku, Tokyo, 152-8551, Japan.
After half a century from their isolation in 1974, we report the first total syntheses of β- and γ-naphthocyclinones, two dimeric pyranonaphthoquinones featuring an unusual bicyclo[3.2.1]-octadienone core.
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