A novel enantioselective divergent route to 13-alkyl derivatives of α- and γ-ionone, important components of perfumes and fragrances, is reported. This relatively short and convenient methodology takes advantage of the use of a common intermediate, easily obtained from highly enantiomerically enriched (S)-α-ionone, which avoids the separate installation of the butenone side chain at C(6) for each analog. Olfactory evaluation of synthesized compounds reconfirmed the influence of the hydrophobic interactions of alkyl substituents at C(5) with olfactory receptors (ORs) in the chemoreception of ionones, and suggested that a synperiplanar orientation of C(13) and the lateral chain is the better geometry fitting OR's cavity.
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http://dx.doi.org/10.1002/cbdv.201400030 | DOI Listing |
Angew Chem Int Ed Engl
December 2024
Department of Chemistry, University of York, Heslington, York, U.K., YO10 5DD.
Unspecific peroxygenases (UPOs) catalyze the selective oxygenation of organic substrates using only hydrogen peroxide as the external oxidant. The PaDa-I variant of the UPO from Agrocybe aegerita catalyses the oxidation of Z- and E-allylic alcohols with complementary selectivity, giving epoxide and carboxylic acid/aldehyde products respectively. Both reactions can be performed on preparative scale with isolated yields up to 80 %, and the epoxidations proceed with excellent enantioselectivity (>99 % ee).
View Article and Find Full Text PDFJ Am Chem Soc
December 2024
College of Chemistry & Materials Engineering, Wenzhou University, Wenzhou 325035, China.
J Am Chem Soc
November 2024
Department of Chemistry, University of California Riverside, Riverside, California 92521, United States.
This manuscript details the development of an asymmetric variant for the Ni-photoredox α-arylation of tetrahydrofuran (THF), which was originally reported in a racemic fashion by Doyle and Molander. Leveraging the enantioselectivity data that we obtained, a complex mechanistic scenario different from those originally proposed is uncovered. Specifically, an unexpected dependence of the product enantiomeric ratio was observed on both the halide identity (aryl chloride vs bromide substrates) and the Ni source.
View Article and Find Full Text PDFJ Am Chem Soc
November 2024
State Key Laboratory of Antiviral Drugs; Collaborative Innovation Centre of Henan Province for Green Manufacturing of Fine Chemicals; Key Laboratory of Green Chemical Media and Reactions, Ministry of Education; NMPA Key Laboratory for Research and Evaluation of Innovative Drug; Henan Key Laboratory of Organic Functional Molecule and Drug Innovation; School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, China.
β-Fluoromethyl (CHF, CHF, and CF)-substituted chiral ketones are essential moieties and are vital building blocks in pharmaceutical and agrochemistry. However, general and convenient methods for enantio-diverse access to diverse β-fluoromethylated ketones are lacking, hindering the further development of these functional moieties. In this study, we developed an ene-reductase-based photobiocatalytic platform for efficient synthesis of enantio-divergent β-fluoromethylated chiral ketones.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
October 2024
Hefei National Research Center for Physical Sciences at the Microscale and Department of Chemistry, University of Science and Technology of China, Hefei, 230026, China.
Oxidative cross-dehydrogenative C-H/C-H functionalizations represent an exemplary approach for synthesizing carbonyl compounds via α-heteroarylation. Here we present the development of a direct anodic oxidative coupling process between 2-acylimidazoles and divergent heterocyclic systems including indole, pyrrole, and furan, facilitated by ferrocene-assisted asymmetric nickel electrocatalysis with high levels of enantioselectivity. Mechanistic investigations indicate that the reaction initially involves the formation of a chiral Ni-bound α-carbonyl radical, which is then captured by the heteroarene radical cation via intermolecular stereoselective radical/radical cation coupling.
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