ABSTRACT
Hydrazides, N-N containing structural motifs, are important due to their presence in a wide variety of biologically significant compounds. While the homo N-N coupling of two NH moieties to form the hydrazide N-N bond is well developed, the cross-dehydrogenative hetero N-N coupling remains very unevolved. Here we present an efficient intermolecular N-N cross-coupling of a series of primary benzamides with broad range of Lewis basic primary and secondary amines using PhI(OAc)2 as both a terminal oxidant and a cross-coupling mediator, without the need for metal catalysts, high temperatures, and inert atmospheres, and with substantial potential for use in the late-stage functionalization of drugs.
ABSTRACT
Here we present an iridium catalysed C2-selective methylation of indoles using methyltrifluoroborate as a source of methyl group. The iridium catalyst selectively discriminates the indole C2 and C4 C-H bonds by coordination with a pivaloyl directing group.
ABSTRACT
The regiochemical outcome of a cobalt(II) catalysed C-H activation reaction of aminoquinoline benzamides with unsymmetrical 1,3-diynes under relatively mild reaction conditions can be steered through the choice of diyne. The choice of diyne provides access to either 3- or 4-hydroxyalkyl isoquinolinones, paving the way for the synthesis of more highly elaborate isoquinolines.
ABSTRACT
Pyrazole and its derivatives are important azole heteroarenes prevalent in pharmaceutical compounds and have been used as ligands for protein binding, making them valuable targets for synthetic applications. Herein we disclose an electrochemical intermolecular C-H/N-H oxidative annulation of 2-phenylpyrazoles with alkynes using a rhodium(III) redox regime without any external metal oxidants in a water compatible solvent system. Both symmetrical and unsymmetrical alkynes were shown to be compatible with the optimized conditions.
ABSTRACT
Described herein is a decarbonylative tandem C-H bis-arylsulfenylation of indole at the C2 and C4 C-H bonds through the use of pentamethylcyclopentadienyl iridium dichloride dimer ([Cp*IrCl2]2) catalyst and disulfides. A new sacrificial electron-rich adamantoyl-directing group facilitates indole C-H bis-functionalization with a traceless in situ removal. Various differently substituted disulfides can be easily accommodated in this reaction by a coordination to Ir(III) through the formation of six- and five-membered iridacycles at the C2 and C4 positions, respectively. Mechanistic studies show that a C-H activation-induced C-C activation is involved in the catalytic cycle.
ABSTRACT
The use of inexpensive base metal catalysis to perform C-H activation is an active field of research in organic synthesis. Described herein is a sustainable cobalt-catalyzed diastereoselective oxidative annulation/double C-H activation of benzothiophene-[b]-1,1-dioxide with aminoquinolinamides under mild reaction conditions for the synthesis of annulated benzothiophenes.
ABSTRACT
A family of non-ionic deep eutectic liquids has been developed based upon mixtures of solid N-alkyl derivatives of urea and acetamide that in some cases have melting points below room temperature. The eutectic behaviour and physical characteristics of a series of eleven eutectic mixtures are presented, along with a molecular dynamics study-supported hypothesis for the origin of the non-ideal mixing of these substances. Their use as solvents in applications ranging from natural product extraction to organic and polymer synthesis are demonstrated.
Subject(s)
Acetamides/chemistry , Solvents/chemistry , Temperature , Urea/chemistry , Hydrogen Bonding , Molecular Dynamics Simulation , Molecular Structure , Solubility , Spectrum AnalysisABSTRACT
Metal-catalyzed cross-coupling reactions are among the most important transformations in organic synthesis. However, the use of C-H activation for sp2 C-N bond formation remains one of the major challenges in the field of cross-coupling chemistry. Described herein is the first example of the synergistic combination of copper catalysis and electrocatalysis for aryl C-H amination under mild reaction conditions in an atom-and step-economical manner with the liberation of H2 as the sole and benign byproduct.
ABSTRACT
Significant enantioselective recognition has been achieved through the introduction of long range ordered and highly interconnected 300 nm diameter pores in molecularly imprinted polymer matrices.
ABSTRACT
The development of a first row transition metal (cobalt)-based catalyst for the as yet unexplored C-H activation-driven reaction of 1,3-diynes, themselves a functional class of interest in a range of application areas, to form isoquinolinones-an important structural motif in a number of biologically active substances-is presented. This versatile and inexpensive catalyst employs a covalently attached bidendate-directing group, 8-aminoquinoline. The template directs the C-H activation and facilitates the synthesis of a wide range of alkynylated heterocycles under mild conditions and with excellent regioselectivity. This strategy provides a novel and efficient route to diverse heterocyclic frameworks as demonstrated by its late stage application in bisheterocycle syntheses.
ABSTRACT
Halogenated arenes are important structural motifs commonly found in biologically active molecules and used for a variety of transformations in organic synthesis. Herein, we report the mono-protected l-amino acid (l-MPAA) accelerated iridium(III)-catalyzed halogenation of (hetero)anilides at room temperature. This reaction constitutes the first example of an iridium(III)/l-MPAA-catalyzed general halogenation of (hetero)arenes through C(sp2 )-H activation. Furthermore, we demonstrate the potential utility of our method through its use in the synthesis of a quinolone derivative.
Subject(s)
Amino Acids/chemistry , Iridium/chemistry , Carbon/chemistry , Catalysis , Halogenation , Hydrogen/chemistry , Quantum TheoryABSTRACT
An efficient Pd-catalyzed stereoselective vinyltrifluoromethylation of aryl halides, through decarboxylative cross-coupling with 2-(trifluoromethyl)acrylic acid is described. The ready availability of the starting materials, the high level of functional group tolerance, and excellent E/Z selectivity make this protocol a safe and operationally convenient strategy for efficient synthesis of vinyltrifluoromethyl derivatives.
Subject(s)
Acrylates/chemistry , Hydrocarbons, Halogenated/chemistry , Hydrocarbons, Halogenated/chemical synthesis , Organometallic Compounds/chemistry , Palladium/chemistry , Catalysis , Decarboxylation , Methylation , Molecular StructureABSTRACT
A copper mediated C-N bond formation for the amidation of aryl halides using 8-aminoquinoline has been developed. This strategy provides efficient access to amides bearing two contiguous heterocyclic moieties and does not require the presence of additional ligands.
Subject(s)
Amides/chemistry , Aminoquinolines/chemistry , Chelating Agents/chemistry , Copper/chemistry , Catalysis , Molecular StructureABSTRACT
A Rh(III) catalysed amino arylation of alkynes using copper as the terminal oxidant for regeneration of the catalytically active species under aerobic conditions is described. This novel C-H activation reaction was applied to the synthesis of a wide range of substituted indoles from N-arylureas.