In the realm of transition-metal catalyzed arene functionalization, rhodium(III) catalysis is considered as exemplary due to its propensity to activate C-H bonds to obtain comprehensive molecular assembly. Herein, we demonstrate a new rhodium(III) catalyzed assembly of polyheterocyclic scaffolds via C-H activation and regioselective annulation of 4-arylbut-3-yn-1-amines with 4-hydroxy-2-alkynoates. Heterocyclization and trans-metalation prior to annulation is the key for initiation of this relay redox-neutral catalytic cascade.
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http://dx.doi.org/10.1021/acs.joc.1c00477 | DOI Listing |
Acc Chem Res
January 2025
Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, Innovative Drug Research Center, School of Pharmaceutical Sciences, Chongqing University, Chongqing 401331, China.
ConspectusThe Mannich reaction, involving the nucleophilic addition of an enol(ate) intermediate to an imine or iminium ion, is one of the most widely used synthetic methods for the synthesis of β-amino carbonyl compounds. Nevertheless, the homo-Mannich reaction, which utilizes a homoenolate intermediate as the nucleophilic partner and provides straightforward access to the valuable γ-amino carbonyl compounds, remains underexplored. This can be largely attributed to the difficulties in generation and manipulation of the homoenolate species, despite various homoenolate equivalents that have been developed.
View Article and Find Full Text PDFACS Catal
October 2024
Center for Heterocyclic Compounds, Department of Chemistry, University of Florida, Gainesville, Florida 32611, United States.
A class of generated Lewis acid (LA) activated acridine complexes is reported, which act as potent photochemical catalysts for the oxidation of a variety of protected secondary amines. Acridine/LA complexes exhibit tunable excited state reduction potentials ranging from +2.07 to 2.
View Article and Find Full Text PDFOrganometallics
January 2025
Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, U.K.
The group 1 alumanyls, [{SiN}AlM] (M = K, Rb, Cs; SiN = {CHSiMeNDipp}), display a variable kinetic facility (K < Rb < Cs) toward oxidative addition of the acidic C-H bond of terminal alkynes to provide the corresponding alkali metal hydrido(alkynyl)aluminate derivatives. Theoretical analysis of the formation of these compounds through density functional theory (DFT) calculations implies that the experimentally observed changes in reaction rate are a consequence of the variable stability of the [{SiN}AlM] dimers, the integrity of which reflects the ability of M to maintain the polyhapto group 1-arene interactions necessary for dimer propagation. These observations highlight that such "on-dimer" reactivity takes place sequentially and also that the ability of each constituent Al(I) center to effect the activation of the organic substrate is kinetically differentiated.
View Article and Find Full Text PDFOrganometallics
January 2025
Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, United Kingdom.
Cyclopentadienyl anions ([Cp]) are pervasive ligands in coordination chemistry. In contrast, heavy-element derivatives of these ligands, particularly those that feature arsenic, are not as well developed. In this work, a new arsenic-based heterocycle with a structure analogous to [Cp] is presented.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
University of Basel, Department of Chemistry, St. Johanns-Ring 19, 4056, Basel, SWITZERLAND.
Despite the growing importance of planar chiral macrocyclophanes owing to their unique properties in different areas of chemistry, methods that are effective in controlling their planar chirality are restricted to certain molecular scaffolds. Herein, we report the first Pd(0)-catalyzed enantioselective intermolecular C-H arylation that induces planar chirality by installing bulky aryl groups through dynamic kinetic resolution (DKR). A computer-assisted approach allowed a fine-tuning of the structure of the employed chiral bifunctional phosphine-carboxylate ligands to achieve high enantioselectivities.
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