Utilizing the C4 reactive site of cyclopropyl ketones and a chiral N,N'-dioxide-scandium(iii) complex as a catalyst, a concise ring-opening/cyclization/thio-Michael cascade method was developed for the synthesis of chiral benzothiazole derivatives from a simple 2-aminothiophenol material. The kinetic resolution and the origin of stereoselectivity were elucidated via a possible catalytic model.
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http://dx.doi.org/10.1039/d0cc05667g | DOI Listing |
J Org Chem
December 2024
State Key Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou 730000, P.R. China.
Herein, the palladium-catalyzed autotandem reaction of cyclopropyl alcohols with gem-dibromoolefins is described. This reaction system involves two distinct mechanistic processes, both efficiently catalyzed by the same palladium catalyst. This approach accommodates a wide substrate scope using readily available starting materials, offering a new and efficient method for synthesizing a series of β-pyrrolo[1,2-]quinolinyl ketones.
View Article and Find Full Text PDFOrg Biomol Chem
December 2024
Department of Material and Chemical Engineering, Zhengzhou University of Light Industry, 136 Science Avenue, 450001, Zhengzhou, Henan Province, P.R. China.
In the present study, the mechanism, origin of chemoselectivity, and substituent effects of the phosphine-catalyzed ring-opening reaction of cyclopropyl ketone have been investigated using the DFT method. Multiple pathways, including the formation of hydrofluorenone, the Cloke-Wilson product, and cyclopenta-fused product, were studied and compared. The computational results show that the pathway for the formation of hydrofluorenone is the most favorable one, which involves four processes: nucleophilic substitution to open the three-membered ring, an intramolecular Michael addition for the formation of an enolate intermediate, an intramolecular [1,5]-proton transfer to give ylide, and an intramolecular Wittig reaction to deliver the final product.
View Article and Find Full Text PDFJ Org Chem
November 2024
Department of Chemistry, School of Natural Sciences, The University of Manchester, ManchesterM13 9PL, U.K.
Org Lett
October 2024
Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, West Bengal, India.
In this study, we have developed an effective and general strategy for synthesizing various 4-[(trifluoromethyl)thio]-2,3-dihydrofuran derivatives with high regioselectivity from easily prepared cyclopropyl ketone under mild reaction conditions. By the combination of photoredox, copper, and Lewis acid catalysis into a triple catalytic system, this methodology facilitates the selective cleavage of the carbon-carbon bonds and the formation of new carbon-oxygen and carbon-sulfur bonds. In addition, to enhance the synthetic feasibility of this protocol, we demonstrate its broad applicability across a wide range of substrates and its scalability for large-scale synthesis.
View Article and Find Full Text PDFChem Sci
August 2024
Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata Mohanpur 741246 West Bengal India
Cyclopentenes serve as foundational structures in numerous natural products and pharmaceuticals. Consequently, the pursuit of innovative synthetic approaches to complement existing protocols is of paramount importance. In this context, we present a novel synthesis route for acyl cyclopentenes through a cascade reaction involving an acceptorless-dehydrogenative coupling of cyclopropyl methanol with methyl ketone, followed by a radical-initiated ring expansion rearrangement of the formed vinyl cyclopropenone intermediate.
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