-difluoroalkenes are an easily accessed fluorinated functional group, and a useful intermediate for elaborating into more complex fluorinated compounds. Currently, most functionalization reactions of -difluoroalkenes, with or without a transition metal-based catalyst system, involve the addition or removal of a fluorine atom to generate trifluorinated or monofluorinated products, respectively. In contrast, we present a complementary "fluorine-retentive" reaction that exploits an organocatalytic strategy to add phenols across -difluoroalkenes to deliver β,β-difluorophenethyl arylethers. The products are produced in good to moderate yields and selectivities, thus providing a range of compounds that are underrepresented in the synthetic and medicinal chemistry literature.
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http://dx.doi.org/10.1016/j.tet.2019.04.016 | DOI Listing |
Org Biomol Chem
January 2025
Key Laboratory of Functional Molecular Solids, Ministry of Education, Anhui Laboratory of Molecule-Based Materials (State Key Laboratory Cultivation Base), College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241002, P.R. China.
An organocatalytic approach for the construction of 2,3-dihydrobenzofuran scaffold through a formal [4 + 1] annulation of 2-(2-nitrovinyl)phenols and α-bromoacetophenones in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) has been developed.
View Article and Find Full Text PDFChem Sci
December 2024
Department of Chemistry, Biology and Biotechnology, University of Perugia Via Elce di Sotto, 8 06123 Perugia Italy
The majority of enantioselective organocatalytic reactions occur in apolar or weakly polar organic solvents. Nevertheless, the influence of solute-solvent van der Waals forces on the relative kinetics of competitive pathways remains poorly understood. In this study, we provide a first insight into the nature and strength of these interactions at the transition state level using advanced computational tools, shedding light into their influence on the selectivity.
View Article and Find Full Text PDFChem Commun (Camb)
December 2024
Department of Chemistry, Indian Institute of Technology Jammu, Jagti, NH-44, Nagrota Bypass, Jammu 181221, J&K, India.
A highly regio-, enantio- and diastereo-selective strategy involving initial enantioselective conjugate addition to 4-nitro-5-styrylisoxazoles serves as a key step for the desymmetrization of 2,5-cyclohexadienones has been disclosed. We have designed a new class of 2,5-cyclohexadienones appended with 4-nitro-5-styrylisoxazoles to undergo organocatalytic asymmetric double or triple conjugate addition in a domino sequence depending on the substrate type leading to desymmetrization of the 2,5-cyclohexadienone core. The developed protocol allows the construction of a valuable hydrophenanthrene core or a unique bridged scaffold bearing multiple chiral centers with excellent enantio- (up to >99.
View Article and Find Full Text PDFJ Org Chem
January 2025
Laboratory of Organo Catalysis and Synthesis, Department of Chemistry, Visvesvaraya National Institute of Technology (VNIT), Nagpur, Maharashtra 440010, India.
A practically intriguing catalytic domino methodology has been developed for the synthesis of highly functionalized pyran and ethene-1,1,2-tricarbonitrile derivatives in a single-pot operation. The -dicyano olefins and the corresponding epoxide were taken as the reactive partners in the presence of a hydrogen bond donor (HBD)-catalyzed condition. The reaction was found to be highly efficient in terms of the formation of sequential C-C and O-C bonds along with an exceptional C-C coupling step through a metal-free organocatalytic pathway.
View Article and Find Full Text PDFOrg Lett
December 2024
Molecular Synthesis Center & Key Laboratory of Marine Drugs, Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, 5 Yushan Road, Qingdao 266003, China.
A regiodivergent strategy for the asymmetric diversity-oriented synthesis of spirooxindoles via organocatalytic cascade reactions is developed. Two regioselective pathways can be precisely controlled with different aminocatalysts in the reaction of 2-hydroxycinnamaldehydes and β,β-disubstituted 3-alkylidene oxindoles. The cascade vinylogous Michael/oxa-Michael/aldol reactions gave spiro-bridged oxindoles bearing two adjacent quaternary stereocenters, while the cascade oxa-Michael/Michael reactions gave spirooxindoles.
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