76215-47-9Relevant articles and documents
Trans Influence of Ligands on the Oxidation of Gold(I) Complexes
Yang, Yangyang,Eberle, Lukas,Mulks, Florian F.,Wunsch, Jonas F.,Zimmer, Marc,Rominger, Frank,Rudolph, Matthias,Hashmi, A. Stephen K.
, p. 17414 - 17420 (2019)
Gold(I) complexes are considered active species toward oxidative addition; current understanding indicates a different mechanism in contrast to other late transition metals, but a rational understanding of the reactivity profile is lacking. Herein, we propose that the accessibility of the gold(I) center to tri- or tetra-coordination is critical in the oxidative process involving a tri- or tetra-coordinate gold(I) with the oxidizing reagent as one of the ligands as an intermediate. A computational study of the geometry of (Phen)R3PAu(I)NTf2 complexes shows that the accessibility of such tricoordinate species shows a good correlation with the "trans influence" of phosphine ligands: the weak σ-donating phosphine ligands promote tricoordination of gold(I) complexes. The oxidative addition to the asymmetric tricoordinate (Phen)R3PAu(I)NTf2 complexes with alkynyl hypervalent iodine reagents was built. The kinetic profile of the oxidative addition exhibits a good relationship to the Hammett substituent parameter (ρ = 3.75, R2 = 0.934), in which the gold(I) complexes bearing less σ-donating phosphine ligands increase the rate of oxidative addition. The positive ρ indicates a high sensitivity of the oxidative addition to the trans influence. The reactivity profile of oxidative addition to a linear bis(pyridine)gold(I) complex further supports that the oxidative addition to gold(I) complexes is promoted by ligands with small trans influence.
A Tautomeric λ3/λ5-Phosphane Pair and Its Ambiphilic Reactivity
M?rsdorf, Jean-Marc,Wadepohl, Hubert,Ballmann, Joachim
, p. 3502 - 3508 (2019)
The central phosphorus atom of a novel hydroxyl-functionalized triarylphosphane was shown to reversibly insert into one of the molecule's O-H bonds, which forms the basis for a tautomeric λ3/λ5-phosphane equilibrium. For the first time, this equilibrium was detected for a λ3-triarylphosphane and the underlying dynamic process was elucidated by NMR spectroscopy. On the basis of reactivity studies, a nucleophilic character was assigned to the minor species present in solution, the λ3-phosphane. Upon methylation, for example, the λ3-form was selectively removed from the equilibrium and converted to the corresponding phosphonium salt. However, upon generation of an alkoxide via proton abstraction, the electrophilic character of the λ5-phosphane in the equilibrium became evident since the alkoxide was found to attack the molecule's phosphorus atom. This intramolecular reaction led to the selective formation of a new anionic λ6-hydridospirophosphane.
Cu(I)-Catalyzed gem-Aminoalkynylation of Diazo Compounds: Synthesis of Fluorinated Propargylic Amines
Pisella, Guillaume,Ramirez, Nieves P.,Waser, Jerome
supporting information, p. 10928 - 10938 (2021/07/31)
The gem-aminoalkynylation of fluorinated diazo compounds catalyzed by a simple Cu(I) salt is described. This three-component reaction allows the synthesis of propargylic amines with broad functional group tolerance. Both electron-rich and electron-poor an
Cys–Cys and Cys–Lys Stapling of Unprotected Peptides Enabled by Hypervalent Iodine Reagents
Ceballos, Javier,Grinhagena, Elija,Sangouard, Gontran,Heinis, Christian,Waser, Jerome
supporting information, p. 9022 - 9031 (2021/03/16)
Easy access to a wide range of structurally diverse stapled peptides is crucial for the development of inhibitors of protein-protein interactions. Herein, we report bis-functional hypervalent iodine reagents for two-component cysteine-cysteine and cysteine-lysine stapling yielding structurally diverse thioalkyne linkers. This stapling method works with unprotected natural amino acid residues and does not require pre-functionalization or metal catalysis. The products are stable to purification and isolation. Post-stapling modification can be accessed via amidation of an activated ester, or via cycloaddition onto the formed thioalkyne group. Increased helicity and binding affinity to MDM2 was obtained for a i,i+7 stapled peptide.
Au–Ag Bimetallic Catalysis: 3-Alkynyl Benzofurans from Phenols via Tandem C?H Alkynylation/Oxy-Alkynylation
Hu, Long,Dietl, Martin C.,Han, Chunyu,Rudolph, Matthias,Rominger, Frank,Hashmi, A. Stephen K.
supporting information, p. 10637 - 10642 (2021/04/06)
The development of new methodologies enabling a facile access to valuable heterocyclic frameworks still is an important subject of research. In this context, we describe a dual catalytic cycle merging C?H alkynylation of phenols and oxy-alkynylation of the newly introduced triple bond by using a unique redox property and the carbophilic π acidity of gold. Mechanistic studies support the participation of a bimetallic gold–silver species. The one-pot protocol offers a direct, simple, and regio-specific approach to 3-alkynyl benzofurans from readily available phenols. A broad range of substrates, including heterocycles, is transferred with excellent functional group tolerance. Thus, this methodology can be used for the late-stage incorporation of benzofurans.
Tetrasubstituted 1,3-Enynes by Gold-Catalyzed Direct C(sp2)-H Alkynylation of Acceptor-Substituted Enamines
Han, Chunyu,Tian, Xianhai,Zhang, Huili,Rominger, Frank,Hashmi, A. Stephen K.
supporting information, p. 4764 - 4768 (2021/06/30)
A gold-catalyzed synthesis of tetrasubstituted 1,3-enynes from hypervalent iodine(III) reagents and activated alkenes is reported. This reaction involves an in situ formed alkynyl Au(III) species and a subsequent direct C(sp2)-H functionalization of alkenes, offering 26 enynes in 62-92% yield with excellent functional group tolerance.
Dual Gold/Silver Catalysis: Indolizines from 2-Substituted Pyridine Derivatives via a Tandem C(sp3)–H Alkynylation/Iminoauration
Han, Chunyu,Liu, Yaowen,Tian, Xianhai,Rominger, Frank,Hashmi, A. Stephen K.
supporting information, p. 9480 - 9484 (2021/12/17)
A dual gold/silver-catalyzed cascade C(sp3)–H alkynylation/iminoauration of 2-substituted pyridines with hypervalent iodine(III) reagents for the synthesis of indolizines is described. This novel reaction involves the formation of an alkynyl Au(III) species, a dual gold/silver-catalyzed C(sp3)–H functionalization, and a subsequent iminoauration process. A number of indolizines bearing diverse functionalities were prepared in good to excellent yield. Furthermore, a gram-scale reaction was efficiently conducted.
Three-Component Reaction for the Synthesis of Highly Functionalized Propargyl Ethers
Pisella, Guillaume,Gagnebin, Alec,Waser, Jér?me
, p. 10199 - 10204 (2020/07/17)
Multicomponent reactions provide efficient means to access molecular complexity. Herein, we report a copper-catalyzed three-component reaction of diazo compounds, alcohols and ethynyl benziodoxole (EBX) reagents for the synthesis of propargyl ethers. Extensive variations of the three partners of the reaction is possible, leading to highly functionalized and structurally diverse products under mild conditions. Alkynylation of a copper ylide intermediate is postulated as key step for this transformation.
Copper-catalyzed oxyvinylation of diazo compounds
Pisella, Guillaume,Gagnebin, Alec,Waser, Jerome
supporting information, p. 3884 - 3889 (2020/05/14)
A copper(I)-catalyzed vinylation of diazo compounds with vinylbenziodoxolone reagents (VBX) as partners is reported. The transformation tolerates diverse functionalities on both reagents delivering polyfunctionalized vinylated products. The strategy was successfully extended to a three-component/intermolecular version with alcohols. The obtained products contain synthetically versatile functional groups, such as an aryl iodide, an ester, and an allylic leaving group, enabling further modification.
Practical synthesis of α,β-Alkynyl ketones by oxidative alkynylation of aldehydes with hypervalent alkynyliodine reagents
Maruoka, Keiji,Sakamoto, Ryu,Tsuzuki, Saori
supporting information, p. 633 - 636 (2020/10/08)
A practical, metal-free carbonyl C(sp2)H oxidative alkynylation of aldehydes with hypervalent alkynyliodine reagents without the use of any catalysts is described for the synthesis of various α,β-alkynyl ketones. Here, two different methods have been developed where limiting reagents or substrates can be switched, and adopted according to the valuableness of aldehyde substrates or hypervalent alkynyliodine reagents. These reactions proceed with a broad substrate scope and high functional-group compatibility.
