Annulations of unsaturated systems through C-H activation represent a powerful tool for producing multicyclic scaffolds. Having coordinating centers in both annulation partners (a dual coordination strategy) would afford remarkable selectivities in the outcomes. Along this concept, we report herein a Pd-catalyzed regioselective rollover cascade dual C-H annulation of -arylphenols with alkynols for constructing phenanthrene scaffolds. Control, KIE and deuteration studies were conducted to determine the reaction mechanism, and downstream transformations and scaled-up reactions were carried out to assess the robustness of the transformation.
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http://dx.doi.org/10.1039/d3cc02523c | DOI Listing |
J Org Chem
December 2024
State Key Laboratory of Antiviral Drugs, Pingyuan Laboratory, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang 453007, Henan, China.
A palladium-catalyzed [2 + 2 + 2] cyclization of 1,6-enynes with unsymmetrical alkynes has been successfully accomplished, resulting in the formation of a series of fused tricyclic hydronaphthofurans with high stereo- and regioselectivity in a single step. This reaction demonstrates 100% atomic economy and exhibits a broad substrate scope.
View Article and Find Full Text PDFChemistry
December 2024
Shanghai Key Laboratory of Green Chemistry and Chemical Processes, State Key Laboratory of Petroleum Molecular & Process Engineering, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, 200062, China.
Pd-catalyzed alkoxycarbonylation of internal alkynes provides a straightforward access to α,β-disubstituted acrylic esters. Compared with the well-established regioselective alkoxycarbonylation of terminal alkynes, the regioselective hydrocarboxylation of non-functionalized unsymmetric internal alkynes was more challenging owing to the delicate differences of properties between the two substituents. Herein, by using either monophosphine ligand based on 2,3-dihydrobenzo[d][1,3]oxaphosphole motif or bidentate ligand Ph-Phox, the regioselective alkoxycarbonylations of aryl-aryl, aryl-alkyl and alkyl-alkyl disubstituted alkynes were achieved, giving a diversity of trisubstituted α,β-unsaturated carboxylic esters with moderate to excellent yields and high regioselectivity.
View Article and Find Full Text PDFJ Org Chem
December 2024
Key Laboratory of Advanced Materials Technologies, International (Hong Kong Macao and Taiwan) Joint Laboratory on Advanced Materials Technologies, College of Materials Science and Engineering, Fuzhou University, Fuzhou, Fujian 350108, China.
The structure-activity relationship between the metal center and regio-selectivity is persistently a pivotal scientific issue. To address this, we select the 2-phenylpyridine sulfonylation reactions catalyzed by ruthenium and palladium as research subjects. An extensive theoretical study has been conducted on their reaction mechanisms, the sources of regio-selectivity, and the evolution of electronic structures.
View Article and Find Full Text PDFJ Org Chem
December 2024
Medicinal Chemistry, Oncology R&D, AstraZeneca, The Discovery Centre, 1 Francis Crick Avenue, Cambridge CB2 0AA, United Kingdom.
The increasing popularity of the dihydrouracil motif in cereblon (CRBN) recruiting proteolysis-targeting chimeras (PROTACs) has necessitated the development of a facile, cost-effective, and high-yielding method for its introduction into molecules. To that end, we disclose herein an N-1 selective Pd-catalyzed cross-coupling of dihydrouracil with aryl electrophiles to provide access to medicinally relevant scaffolds in a single step. This approach exhibits excellent functional group tolerance and broad applicability to an abundance of (hetero)aryl halides and phenol derivatives and utilizes readily available catalyst/ligand systems.
View Article and Find Full Text PDFJ Org Chem
December 2024
Universitaet Potsdam, Institut fuer Chemie, Karl-Liebknecht-Straße 24-25, D-14476 Potsdam-Golm, Germany.
The synthesis of coumarin- and flavonoid-chalcone hybrids via Pd-catalyzed Heck-type coupling of arene diazonium salts and 8-allylcoumarins and -flavonoids is reported. The β-hydride elimination step proceeds with high regioselectivity if an OMOM-substituent is present at the position C7, adjacent to the allyl group. A selective allylic oxidation of the coupling products was accomplished using DDQ in the presence of silica to furnish the chalcones.
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