In this manuscript, the first enantioselective dearomative Michael addition between α,β-unsaturated aldehydes and 2-nitrobenzofurans realized under N-heterocyclic carbene activation has been described. The reaction proceeds addition of homoenolate to Michael acceptors leading to the formation of biologically important heterocycles with high yields and stereoselectivities. Their functionalization potential has been confirmed in selected, diastereoselective transformations.
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http://dx.doi.org/10.1039/d2cc00294a | DOI Listing |
J Am Chem Soc
October 2024
State Key Laboratory of Chemical Oncogenomics, Shenzhen Key Laboratory of Chemical Genomics, AI for Science (AI4S) Preferred Program, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen 518055, P. R. China.
Creating artificial enzymes by the genetic incorporation of noncanonical amino acids with catalytic side chains would expand the enzyme chemistries that have not been discovered in nature. Here, we report the design of an artificial enzyme that uses -boronophenylalanine as the catalytic residue. The artificial enzyme catalyzes Michael-type Friedel-Crafts alkylation through covalent activation.
View Article and Find Full Text PDFChem Commun (Camb)
August 2024
School of Chemistry & Materials Science, Jiangsu Normal University, Xuzhou, 221116, China.
A highly enantioselective Pd/Bim-catalyzed dearomative Michael reaction applying polycyclic tropones as non-benzenoid aromatic Michael acceptors and arylboronic acids as aryl pronucleophiles has been developed. The bridged biaryls bearing central and axial chirality, including pentacyclic cyclohepta[]indoles and 6,7-dihydrodibenzo[,][7]annulen-5-ones, are generally generated in good to high yields and excellent enantioselectivities and can be readily transformed into useful derivatives.
View Article and Find Full Text PDFOrg Lett
June 2024
Department of Organic Synthesis and Process Chemistry, CSIR-Indian Institute of Chemical Technology, Hyderabad, Telangana 500007, India.
Herein, we reveal an unprecedented domino annulation of -benzyl-acrylamides with 1,3-dicarbonyls for the assembly of fused tricyclic alkaloid frameworks incorporating a spirocycle via an alkylation/dearomative -annulation/Michael addition (desymmetrization) sequence. This conversion involves three carbon-carbon bond formations, generating four chiral carbons, including three quaternary carbon centers, in a single diastereomer in one pot under identical reaction conditions. The synthetic potential of this atom-economic method is illustrated by modifications of the functional groups present in the products obtained.
View Article and Find Full Text PDFJ Org Chem
June 2024
State Key Laboratory of Antiviral Drugs, Pingyuan Laboratory, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang 453007, Henan, China.
A base-assisted dearomative [2 + 1] spiroannulation of /-bromophenols with activated olefins (methylenemalonates) to construct various cyclopropyl spirocyclohexadienone skeletons is reported. Furthermore, several other halophenols (X = Cl, I) were also tolerated in this process. Control experiments reveal a dearomative Michael addition of phenols at their halogenated positions to methylenemalonates, followed by intramolecular radical-based S1 dehalogenative cyclopropanation.
View Article and Find Full Text PDFOrg Lett
April 2024
Department of Chemistry, Indian Institute of Technology Guwahati, North Guwahati, Assam 781039, India.
Herein, an organocatalytic asymmetric dearomative spirocyclization/oxa-Michael addition sequence with a newly designed substrate having two naphthol motifs has been developed. The reaction proceeds through in situ chiral vinylidene -quinone methide (VQM) intermediate formation, dearomative spirocyclization of naphthol, and an oxa-Michael addition reaction. The densely functionalized tetralone products were formed in high yields with high diastereo- and enantioselectivities.
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