The study of the enantioselective fluorination of homoallylic alcohols chiral anion phase transfer (CAPT) catalysis using an generated directing group is described. Multivariate correlation analysis, including designer π-interaction derived parameters, revealed key structural features affecting the selectivity at the transition state (TS). Interpretation of the parameters found in the model equation highlights the key differences as well as similarities for the reaction of homoallylic and allylic substrates. A similar T-shaped π-interaction was found to occur between the substrate and the catalyst. The tuning of this crucial interaction by identification of the best combination of phosphoric acid catalyst and boronic acid directing group allowed for the development of a methodology to access γ-fluoroalkenols in typically high enantioselectivities (up to 96% ee).
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http://dx.doi.org/10.1039/c8sc02223b | DOI Listing |
J Am Chem Soc
December 2024
State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Frontiers Science Center for New Organic Matter, Nankai University, Tianjin 300071, China.
The direct enantioselective functionalization of C(sp)-H bonds in organic molecules could fundamentally transform the synthesis of chiral molecules. In particular, the enantioselective oxidation of these bonds would dramatically change the production methods of chiral alcohols and esters, which are prevalent in natural products, pharmaceuticals, and fine chemicals. Remarkable advances have been made in the enantioselective construction of carbon-carbon and carbon-nitrogen bonds through the C(sp)-H bond functionalization.
View Article and Find Full Text PDFOrg Lett
December 2024
School of Chemical and Environmental Engineering and Shanghai Engineering Research Center of Green Fluoropharmaceutical Technology, Shanghai Institute of Technology, Shanghai 201418, P. R. China.
The construction of chiral tetrasubstituted α-fluoro-α-cyano carbonyl compounds remains a key challenge in synthetic organic chemistry because of their popularity in multiple disciplines. In this paper, we report the copper-catalyzed asymmetric fluorinated tertiary radical cyanation reaction of cyclic α-iodo-α-fluoroindanones with TMSCN to achieve chiral nitriles with carbon-fluorine quaternary stereogenic centers. Thus, an array of optically active tetrasubstituted monofluoroacyl nitriles were synthesized with high reaction efficiency and excellent enantioselectivities (up to 91% yield, 99% ee).
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
December 2024
Department of Chemistry, Johns Hopkins University; Baltimore, Maryland 21218, United States.
The trifluoromethyl (-CF) group represents a highly prevalent functionality in pharmaceuticals. Over the past few decades, significant advances have been made in the development of synthetic methods for trifluoromethylation. In contrast, there are currently no metalloenzymes known to catalyze the formation of C(sp)-CF bonds.
View Article and Find Full Text PDFJ Am Chem Soc
December 2024
Key Laboratory of Fluorine and Nitrogen Chemistry and Advanced Materials, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China.
Catalytic asymmetric α-alkylation of simple carboxylic acid derivatives is a challenging issue due to the difficulties in achieving high catalytic efficiency and controlling the enantioselectivity. Herein, by using a copper(I)-()-DTBM-SEGPHOS complex as a catalyst and 2-acylimidazoles as pronucleophiles, a general method for the catalytic asymmetric α-alkylation of simple carboxylic acid derivatives is accomplished. Various alkyl electrophiles, including allyl bromides, benzyl bromides, propargyl bromide, and unactivated alkyl sulfonates, serve as efficient alkylation reagents.
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