The study of Pd-catalysed cyclisation reactions of alkenols using different catalytic systems is reported. These transformations affect the stereoselective construction of mono- and/or bicyclic oxaheterocyclic derivatives depending on a starting alkenol. The substrate scope and proposed mechanism of Pd-catalysed cyclisation reactions are also discussed. Moreover, the diastereoselective Pd-catalysed cyclisation of appropriate alkenols to tetrahydrofurans and subsequent cyclisation provided properly substituted 2,5-dioxabicyclo[2.2.1]heptane and 2,6-dioxabicyclo[3.2.1]octane, respectively. Such bicyclic ring subunits are found in many natural products including ocellenynes and aurovertines.
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http://dx.doi.org/10.3762/bjoc.10.216 | DOI Listing |
Dalton Trans
December 2024
Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 2030, 128 00 Prague, Czech Republic.
C-H bond functionalisation has developed into a powerful synthetic methodology that is applicable to a wide array of substrates, including organometallic compounds. In this study, racemic, planar-chiral 1,2-dihydroferroceno[]isoquinoline and analogous helical compounds with one or two additional -fused benzene rings were synthesised by palladium-catalysed C-H bond activation/cyclisation of -[(bromoaryl)methyl]--(methylsulfonyl)aminoferrocenes. These starting materials are readily accessible from FcNHSOMe (Fc = ferrocenyl) and appropriate vicinal bromo-(bromomethyl)arenes.
View Article and Find Full Text PDFOrg Biomol Chem
November 2022
School of Chemistry, University of Hyderabad, Hyderabad 500 046, Telangana, India.
Palladium-catalysed and base-dependent intra-molecular -substitution and cyclisation strategies involving -indolyl-substituted aryl-sulfonamides for the rapid construction of 2-aryl indole and indole-fused six-membered sultams are described. The Pd(OAc)/PhP/EtN combination delivers indolyl C2 arylated motifs C(2)-N bond cleavage followed by C-C bond formation. In sharp contrast to this, the Pd(OAc)/PhP/KCO combination induced intramolecular-Heck cross-coupling affords polycyclic sultams exclusively.
View Article and Find Full Text PDFOrg Biomol Chem
August 2021
School of Chemistry, University of Hyderabad, Hyderabad 500 046, Telangana, India.
An efficient and straightforward Pd-catalysed synthesis of diversely substituted sultams utilising ynamides and boronic acids is disclosed; toluene was found to be the most suitable solvent for this transformation. This strategy has been successfully applied to generate dihydrobenzo[d]isothiazole 1,1-dioxides and dihydro-2H-benzo[e][1,2]thiazine 1,1-dioxides. The advantages of this protocol are good functional group tolerance, broad substrate scope, high-yielding reaction and low catalyst loading to access benzofused sultams with five-/six-membered rings.
View Article and Find Full Text PDFMolecules
June 2021
Dipartimento di Biotecnologie, Chimica e Farmacia, Università degli Studi di Siena, Via A. Moro 2, 53100 Siena, Italy.
The synthesis of 2-substituted indoles starting from the corresponding unprotected 2-alkynylanilines was made possible in 3% TPGS-750-M water using Pd(OAc) alone as the catalyst. The reaction was sensitive to the heating mode respect to the nature of the starting material as, in many cases, convectional heating was better than microwave dielectric heating. The MW (microwave) delivery mode had also an influence in the formation of by-products and, consequently, product yields.
View Article and Find Full Text PDFBeilstein J Org Chem
September 2014
Department of Organic Chemistry Slovak University of Technology, Radlinského 9, SK-812 37 Bratislava, Slovakia.
The study of Pd-catalysed cyclisation reactions of alkenols using different catalytic systems is reported. These transformations affect the stereoselective construction of mono- and/or bicyclic oxaheterocyclic derivatives depending on a starting alkenol. The substrate scope and proposed mechanism of Pd-catalysed cyclisation reactions are also discussed.
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