Chan-Lam Coupling Research Articles

Single‐Step Modular Synthesis of Unsaturated Morpholine N‐Oxides and Their Cycloaddition Reactions

AbstractA single‐flask procedure for the generation of α‐keto‐N‐alkenylnitrones through a Chan–Lam coupling and subsequent spontaneous 6π electrocyclization of these intermediates for the synthesis of 2H‐1,4‐oxazine N‐oxides has been developed for a variety of α‐ketooximes and alkenylboronic acids. This transformation provides a new approach to C‐substituted unsaturated morpholine derivatives that are poised to undergo further functionalization for the preparation of a diverse array of novel heterocyclic structures. The scope of the new method for the synthesis of 2H‐1,4‐oxazine N‐oxides is discussed, in addition to initial studies describing the cycloaddition reactivity of these new heterocyclic intermediates.

Single‐Step Modular Synthesis of Unsaturated Morpholine N‐Oxides and Their Cycloaddition Reactions

A single-flask procedure for the generation of α-keto-N-alkenylnitrones through a Chan-Lam coupling and subsequent spontaneous 6π electrocyclization of these intermediates for the synthesis of 2H-1,4-oxazine N-oxides has been developed for a variety of α-ketooximes and alkenylboronic acids. This transformation provides a new approach to C-substituted unsaturated morpholine derivatives that are poised to undergo further functionalization for the preparation of a diverse array of novel heterocyclic structures. The scope of the new method for the synthesis of 2H-1,4-oxazine N-oxides is discussed, in addition to initial studies describing the cycloaddition reactivity of these new heterocyclic intermediates.

Synthesis of α-oxygenated ketones and substituted catechols via the rearrangement of N-enoxy- and N-aryloxyphthalimides

A common approach to the synthesis of α-oxygenated carbonyl compounds and catechols is the treatment of a carbonyl compound or a phenol with an electrophilic oxygen source. As an alternative approach to these important structures, formal [3,3]-rearrangements of N-enoxyphthalimides, N-enoxyisoindolinones, and N-aryloxyphthalimides have been explored. When used in combination with an initial Chan-Lam coupling, these transformations facilitate the dioxygenation of alkenylboronic acids for the synthesis of α-oxygenated ketones and the dioxygenation of arylboronic acids for the synthesis of catechols. The rearrangements of N-enoxyisoindolinones have also been shown to be diastereoselective.

Cu2(BDC)2(BPY)–MOF: an efficient and reusable heterogeneous catalyst for the aerobic Chan–Lam coupling prepared via ball-milling strategy

Nanoporous Cu2(BDC)2(BPY)–MOF was used as efficient and reusable heterogeneous catalyst to effect the aerobic cross-coupling of aromatic amines and phenyl boronic acid (Chan–Lam Coupling).

Cu(II) salen complex with propylene linkage: An efficient catalyst in the formation of C[sbnd]X bonds (X = N, O, S) and biological investigations

The catalytic property of a mononuclear Cu(II) salen complex in Chan-Lam coupling reaction with phenyl boronic acid at room temperature is reported. The studied complex is found to be potential catalyst in the preparation of carbon-heteroatom bonds with excellent yields. The studied Cu(II) salen complex is monoclinic with cell parameters, a = 9.6807(5) (α 90°), (b = 17.2504(8) (β 112.429 (2), c = 11.1403 (6) (γ = 90°), and has distorted square planar environment around Cu(II) ion. Furthermore, there is no π⋯π interactions in the reported complex due to large distance between the centroid of aromatic rings.In addition, DNA binding study of Cu(II) salen complex by fluorescence and absorption spectroscopy is also reported. Moreover, the reported Cu(II) salen complex exhibits significant anticancer activity against MCF-7 cancer cell lines, and displays potential antimicrobial biofilm activity against P. aeruginosa, suggesting antimicrobial biofilm an important tool for suppression of resistant infections caused by P. aeruginosa.

ChemInform Abstract: A Highly Efficient Heterogeneous Copper‐Catalyzed Chan‐Lam Coupling Between Thiols and Arylboronic Acids Leading to Diaryl Sulfides under Mild Conditions.

Abstract The heterogeneous Chan-Lam coupling reaction between thiols and arylboronic acids was achieved in EtOH at room temperature in the presence of 5 mol % of MCM-41-immobilized 1,10-phenanthroline-copper(II) complex [MCM-41-1,10-Phen-CuSO4] with n-Bu4NOH (40% aq) as base under O2 atmosphere, yielding a variety of unsymmetrical diaryl sulfides in good to excellent yields under mild and green conditions. The new heterogeneous copper complex can easily be prepared by a simple procedure from commercially readily available and inexpensive reagents, and recovered by a simple filtration of the reaction solution and recycled for at least eight times without significant loss of catalytic activity.

ChemInform Abstract: A Highly Efficient Heterogeneous Copper‐Catalyzed Chan—Lam Coupling Reaction of Sulfonyl Azides with Arylboronic Acids Leading to N‐Arylsulfonamides.

AbstractThe use of the novel silica supported catalyst (CUP) allows the synthesis of a wide range of N‐arylsulfonylamides at room temperature under air without the need for any base or additive.

Catalytic Chan–Lam coupling using a ‘tube-in-tube’ reactor to deliver molecular oxygen as an oxidant

A flow system to perform Chan–Lam coupling reactions of various amines and arylboronic acids has been realised employing molecular oxygen as an oxidant for the re-oxidation of the copper catalyst enabling a catalytic process. A tube-in-tube gas reactor has been used to simplify the delivery of the oxygen accelerating the optimisation phase and allowing easy access to elevated pressures. A small exemplification library of heteroaromatic products has been prepared and the process has been shown to be robust over extended reaction times.

A highly efficient heterogeneous copper-catalyzed Chan-Lam coupling between thiols and arylboronic acids leading to diaryl sulfides under mild conditions

The heterogeneous Chan-Lam coupling reaction between thiols and arylboronic acids was achieved in EtOH at room temperature in the presence of 5 mol % of MCM-41-immobilized 1,10-phenanthroline-copper(II) complex [MCM-41-1,10-Phen-CuSO4] with n-Bu4NOH (40% aq) as base under O2 atmosphere, yielding a variety of unsymmetrical diaryl sulfides in good to excellent yields under mild and green conditions. The new heterogeneous copper complex can easily be prepared by a simple procedure from commercially readily available and inexpensive reagents, and recovered by a simple filtration of the reaction solution and recycled for at least eight times without significant loss of catalytic activity.

ChemInform Abstract: A Quick Chan—Lam C—N and C—S Cross Coupling at Room Temperature in the Presence of Square Pyramidal [Cu(DMAP)4I]I as a Catalyst.

A rapid and efficient protocol for C–N and C–S cross coupling has been developed using a new square pyramidal copper complex, [Cu(DMAP)4I]I. The complex was successfully synthesized via a disproportionation reaction of CuI and DMAP in DMSO. The catalytic activity of the complex was found to be excellent for Chan–Lam coupling reaction between aryl boronic acid and amine, amide, azide or thiol. The reaction could be carried out in the presence of only 2 mol% of the copper catalyst in methanol at room temperature within a short time.

Chemoselectivity and the Chan-Lam Coupling Reaction: Adding Amino Acids to Polymer-Coated Microelectrode Arrays.

The placement of a peptide onto a microelectrode array is frequently complicated by the presence of multiple nucleophiles in the peptide. In the work reported here, we have found that the Chan-Lam coupling reactions used to site-selectively place thiol, alcohol, and amine nucleophiles onto diblock-copolymer-coated surfaces are chemoselective for the placement of thiol and alcohol nucleophiles on the arrays. This means that cysteine- and serine-containing peptides can be placed onto an array without any need to protect the N terminus of the peptide. Furthermore, it was found that placement of thiol groups onto an array with the Chan-Lam reaction using optimized reaction times leads to complete coverage of the electrodes. The extent of this coverage can be controlled by varying the reaction time in a manner that allows for the construction of arrays with a gradient of peptide concentrations.

A highly efficient heterogeneous copper-catalyzed Chan–Lam coupling reaction of sulfonyl azides with arylboronic acids leading to N-arylsulfonamides

A highly efficient and practical method for the synthesis ofN-arylsulfonamides has been developed by a heterogeneous copper-catalyzed Chan–Lam coupling between sulfonyl azides and boronic acids.

Synthesis, Characterisation and Biological Evaluation of Quinazoline Derivatives as Novel Anti-Microbial Agents

A novel series of Quinazolines were synthesised by cyclisation reaction of Anthranilic acid with urea to get 2,4 di hydroxy quinazoline (2) intermediate, which were further treated with POCl3 to get 2,4 di chloro quinazoline (3), which was treated with Thio-morpholine (4) for 3 hrs to get compounds (5), which are reacted with aqueous ammonia to get compound(6), which was further reacts with different boronic acids 7(a-j) by using Chan-Lam coupling reaction conditions to get Target Novel Quinazoline derivatives (8a-8j). The structures of new compounds were confirmed by IR and 1H NMR and 13C NMR spectral data. Anti-bacterial and anti-fungal activities were evaluated and compared with the standard drugs, compounds 8i, 8d, 8h, 8g exhibited promising anti-microbial and anti-fungal activity compared to standard drugs.

ChemInform Abstract: Visible‐Light‐Mediated Chan—Lam Coupling Reactions of Aryl Boronic Acids and Aniline Derivatives.

The copper(II)-catalyzed aerobic oxidative coupling reaction between aryl boronic acids and aniline derivatives was found to be improved significantly under visible-light-mediated photoredox catalysis. The substrate scope of this oxidative Chan–Lam reaction was thus expanded to include electron-deficient aryl boronic acids as viable starting materials.

A porous metal–organic framework as active catalyst for multiple C–N/C–C bond formation reactions

A 3D porous metal–organic framework {[Cu(4-tba)2](solvent)}n (1⋅S) is assembled via 4-(1H-1,2,4-triazol-1-yl)benzoic acid (Htba) and Cu(II) nodes, which shows the [2+2] roto-translational interpenetrating network. Interestingly, 1 displays high CO2 adsorption selectivity over CH4/H2/O2/Ar/N2 gases, and acts an efficient catalyst precursor in some C–N/C–C bond formation reactions, including Chan–Lam coupling reaction of phenylboronic acid with imidazole, Suzuki–Miyoura coupling reaction of phenylboronic acids with aryl halides, and Heck coupling reaction of styrene with aryl halides.

ChemInform Abstract: A Synthetic Approach to N‐Aryl Carbamates via Copper‐Catalyzed Chan—Lam Coupling at Room Temperature.

AbstractA one‐pot, two‐step synthesis of ureas (IX) using on‐site prepared crude carbamates and secondary amines [cf.

Visible‐Light‐Mediated Chan–Lam Coupling Reactions of Aryl Boronic Acids and Aniline Derivatives

AbstractThe copper(II)‐catalyzed aerobic oxidative coupling reaction between aryl boronic acids and aniline derivatives was found to be improved significantly under visible‐light‐mediated photoredox catalysis. The substrate scope of this oxidative Chan–Lam reaction was thus expanded to include electron‐deficient aryl boronic acids as viable starting materials.

Visible‐Light‐Mediated Chan–Lam Coupling Reactions of Aryl Boronic Acids and Aniline Derivatives

The copper(II)-catalyzed aerobic oxidative coupling reaction between aryl boronic acids and aniline derivatives was found to be improved significantly under visible-light-mediated photoredox catalysis. The substrate scope of this oxidative Chan-Lam reaction was thus expanded to include electron-deficient aryl boronic acids as viable starting materials.

A synthetic approach to N-aryl carbamates via copper-catalyzed Chan-Lam coupling at room temperature.

A mild and efficient synthesis of N-arylcarbamates was achieved by reacting azidoformates with boronic acids in the presence of 10 mol % of copper chloride catalyst. The reaction proceeds readily in an open flask at room temperature without additional base, ligand, or additive. Rapid access to urea analogues via a two-step one-pot procedure is enabled by reacting N-arylcarbamates with aluminum-amine complexes. In addition, among several boronic acid derivatives prepared, dimethylphenyl boronate was found to react rapidly in its reaction with benzyl azidoformate, invoking in situ generation of this species in the catalytic cycle.

Modification of 3,5-Dioxo-2-phenyl-2,3,4,5-tetrahydro-1,2,4-triazine-6-carbonitrile via Mitsunobu and Chan-Lam Coupling Reaction

Modification of 3,5-Dioxo-2-phenyl-2,3,4,5-tetrahydro-1,2,4-triazine-6-carbonitrile via Mitsunobu and Chan-Lam Coupling Reaction