Kei Muto

The first nickel-catalyzed C-H bond arylation of azoles with phenol derivatives is described. The new Ni(cod)(2)/dcype catalytic system is active for the coupling of various phenol derivatives such as esters, carbamates, carbonates, sulfamates, triflates, tosylates, and mesylates. With this C-H/C-O biaryl coupling, we synthesized a series of privileged 2-arylazoles, including biologically active alkaloids. Moreover, we demonstrated the utility of the present reaction for functionalizing estrone

The Suzuki-Miyaura cross-coupling is a metal-catalysed reaction in which boron-based nucleophiles and halide-based electrophiles are reacted to form a single molecule. This is one of the most reliable tools in synthetic chemistry, and is extensively used in the synthesis of pharmaceuticals, agrochemicals and organic materials. Herein, we report a significant advance in the choice of electrophilic coupling partner in this reaction. With a user-friendly and inexpensive nickel catalyst, a range of

We describe mechanistic studies of a C-H/C-O biaryl coupling of 1,3-azoles and aryl pivalates catalyzed by Ni(cod)2/dcype. This study not only supports a catalytic cycle consisting of C-O oxidative addition, C-H nickelation, and reductive elimination but also provides insight into the dramatic ligand effect in C-H/C-O coupling. We have achieved the first synthesis, isolation and structure elucidation of an arylnickel(II) pivalate, which is an intermediate in the catalytic cycle after oxidative a

Functionalization of arenes is a topic of central importance in diverse fields ranging from medicinal chemistry to materials science. Metal-catalyzed cross-coupling and nucleophilic aromatic substitution are among the most reliable methods to access functionalized arenes. In these reactions, haloarenes are often used as a versatile synthetic platform to introduce various functional groups. However, haloarenes are typically prepared from the corresponding nitroarenes through the classic sequence

The first nickel-catalyzed C-H arylations and alkenylations of imidazoles with phenol and enol derivatives are described. Under the influence of Ni(OTf)₂/dcype/K₃PO₄ (dcype: 1,2-bis(dicyclohexylphosphino)ethane) in <i>t</i>-amyl alcohol, imidazoles can undergo C-H arylation with phenol derivatives. The C-H arylation of imidazoles with chloroarenes as well as that of thiazoles and oxazoles with phenol derivatives can also be achieved with this catalytic system. By

The first palladium-catalyzed decarbonylative coupling of phenyl 2-azinecarboxylates and arylboronic acids is presented. The key for the development of this decarbonylative coupling is the use of Pd/dcype as a catalyst. A wide range of 2-azinecarboxylates can undergo the present coupling reaction to afford 2-arylazines. By combination with previously reported nickel-catalyzed decarbonylative coupling, we achieved a chemoselective sequential decarbonylative coupling of pyridine dicarboxylate to s

A catalytic dearomative three-component reaction of bromoarenes with TMS-diazomethane and allyl borate was developed. The key of this assembling reaction is the use of a diazo compound to generate a Pd-π-benzyl intermediate through a Pd-carbene species. This method allowed for a dearomative functionalization, using arenes as limiting reagents. Heteroaryl bromides were also applicable to give dearomatized structures under the reaction conditions.

Dearomative C-C bond formation of benzyl phosphates has been developed. In the presence of a palladium/PAr₃ catalyst, benzyl phosphates reacted with allyl borates to generate the allylated product in a dearomative fashion. The resulting dearomatized molecules were successfully derivatized by Simmons-Smith cyclopropanation and oxidation.

A Pd-catalyzed dearomative three-component C-C bond formation of bromoarenes with diazo compounds and malonates was developed. Various bromoarenes ranging from benzenoids to azines and heteroles were transformed to the corresponding substituted alicyclic molecules. The key to this reaction is the generation of a benzyl-palladium intermediate, which reacts with malonates to form a Pd-<i>O</i>-enolate species. Strikingly, the present method enabled rapid access to multi-substituted alicycles throu

1-Azaspirocyclic compounds have gained attention in chemistry and drug discovery fields. In this manuscript, the development of a Pd-catalyzed dearomative azaspirocyclization of bromoarenes bearing an aminoalkyl group with N-tosylhydrazones is described. The present method enables azaspirocyclization with the introduction of carbon substituents, achieving the convergent synthesis of 1-azaspirocycles. This method allowed furan, thiophene, and naphthalene cores to generate the corresponding 1-azas

A dearomative allylation of naphthyl cyanohydrins with allyl borates and allyl stannanes under palladium catalysis was developed. At the initial stage of this study, the dearomative reaction (C4 substitution of the aromatics) was competing with benzyl substitution. To circumvent this issue, the use of palladium and <i>meta</i>-disubstituted triarylphosphine as the catalyst in a 1:1 ratio was found to enhance the site selectivity, furnishing the desired dearomatized products. Further derivatizati

A dearomative C4-allylation of benzyl ammoniums with allyltributylstannane by a palladium catalysis is described. A triarylphosphine-ligated palladium catalyst, which is capable of cleaving benzylic C–N bonds, realized facile dearomative reactions with C4 selectivity. Combined with precedented C2- and C3-selective functionalizations of benzyl amine derivatives, the present reaction can provide a new synthetic option for the synthesis of multi-substituted alicyclic compounds as well as aromatic c

A palladium-catalyzed 1,4-carboamination of bromoarenes with diazo compounds and amines was developed. This reaction proceeds through a palladium-carbene that then generates a π-benzylpalladium intermediate, forming <i>ipso</i> C-C and <i>para</i> C-N bonds on bromoarenes in a regioselective manner. The successful application of this transformation to the rapid synthesis of an antitumor agent demonstrates its synthetic utility.

The synthesis and catalytic activity of pyridine-fused triazolylidene as a novel abnormal <i>N</i>-heterocyclic carbene (<i>a</i>NHC) ligand is described. The evaluation of physical properties using X-ray crystallographic analysis and infrared spectroscopy revealed that these triazolylidenes have a high electron-donating ability toward the metal center. The application of this triazolylidene to the palladium-catalyzed cross-coupling of chloroarenes and nitroarenes with arylboronic acids showcase

Abstract Total syntheses of C11‐oxygenated Cephalotaxus alkaloids, fortuneicyclidins A and B, and cephalotine B, were achieved. The key for the synthesis is a Pd‐catalyzed dearomative spirocyclization of bromofurans with N ‐tosylhydrazones, followed by acid‐mediated tandem transformation to construct the tetracyclic skeleton with the C11‐oxygen functional group. Chemo‐selective and catalytic functional group conversions of the tetracyclic intermediate completed the synthesis of fortuneicyclidins