[(NHC)AuCl] complexes (NHC = N-heterocyclic carbene), in conjunction with a silver salt, were found to efficiently catalyze the rearrangement of allylic acetates under both conventional and microwave-assisted heating. The optimization of several reaction parameters (solvent, silver salt, and ligand) as well as a study of the reaction scope are reported. The steric hindrance of the ligand bound to gold was found crucial for the outcome of the reaction as only extremely bulky ligands permitted the isomerization.
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http://dx.doi.org/10.1021/ol070843w | DOI Listing |
J Am Chem Soc
January 2025
Laboratory of Synthesis and Natural Products (LSPN), Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne, EPFL-SB-ISIC-LSPN, BCH 5304, CH-1015 Lausanne, Switzerland.
In the dyotropic rearrangement of molecules with semiflexible structures, characterized by a freely rotating static C-C bond, the formation of a mixture of products is common due to the coexistence of several energetically comparable conformers. Herein, we report that it is possible to modulate the shifting groups by adjusting the metal's coordination sphere in Pd-based dyotropic rearrangement. In the presence of a catalytic amount of Pd(II) salt, the reaction of γ-hydroxyalkenes or γ,δ-dihydroxyalkenes with Selectfluor affords fluorinated tetrahydropyranols or 6,8-dioxabicyclo[3.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
School of Chemistry, Dalian University of Technology, Dalian, 116024, P. R. China.
The Pd-catalyzed asymmetric hydrogenolysis rearrangement of allylic acetates using (s-Bu)BHK has been described, achieving the synthesis of axially chiral alkylidene cycloalkanes with excellent enantioselectivities (up to 99 % ee) and a wide substrate scope (30 examples of cyclohexanes and cyclobutanes). To the best of our knowledge, this is the first time to achieve synthesis of axially chiral olefins via asymmetric hydrogenolysis of allylic acetates. This methodology not only offers a novel synthetic pathway for non-atropisomeric axially chiral structures but also highlights the potential of asymmetric hydrogenolysis as a powerful tool in synthetic organic chemistry.
View Article and Find Full Text PDFChem Commun (Camb)
January 2025
School of Chemistry, Cardiff University, Main Building, Park Place, CF10 3AT, Cardiff, UK.
Terpene synthases produce a wide number of hydrocarbon skeletons by controlling intramolecular rearrangements of allylic pyrophosphate subtrates reactive carbocation intermediates. Here we review recent research focused on engineering terpene synthases and modifying their substrates to rationally manipulate terpene catalyisis. Molecular dynamic simulations and solid state X-ray crystallography are powerful techniques to identify substrate binding modes, key active site residues for substrate folding, and the location of active site water.
View Article and Find Full Text PDFJ Org Chem
January 2025
Beijing National Laboratory of Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry, Peking University, Beijing 100871, China.
The construction of C-C bonds to form all-carbon quaternary centers remains a significant challenge in synthetic chemistry. Herein, we report a tandem process involving a 1,2-migration of a tetra-coordinated boron intermediate followed by a Claisen rearrangement of the boron enolate, achieved through a reaction between allyl diazoacetates and trialkylboranes. The transformation forms two C-C bonds at the carbenic position of diazo substrate in a single-step operation under neutral conditions.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
EaStCHEM, School of Chemistry, University of St Andrews, North Haugh, St. Andrews, KY16 9ST, U.K.
The [1,2]-rearrangement of allylic ammonium ylides is traditionally observed as a competitive minor pathway alongside the thermally allowed [2,3]-sigmatropic rearrangement. Concerted [1,2]-rearrangements are formally forbidden, with these processes believed to proceed through homolytic C-N bond fission of the ylide, followed by radical-radical recombination. The challenges associated with developing a catalytic enantioselective [1,2]-rearrangement of allylic ammonium ylides therefore lie in biasing the reaction pathway to favor the [1,2]-reaction product, alongside controlling a stereoselective radical-radical recombination event.
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