Yoshihiko Yamamoto

Transition-metal (TM)-catalyzed hydroarylation reactions of alkynes have received much attention, because they enable the net insertion of alkyne C-C triple bonds into C-H bonds of aromatic precursors, resulting in regio- and stereo-selective formation of synthetically useful arylalkenes. Taking advantage of this feature, TM-catalyzed alkyne hydroarylations have been successfully used for the synthesis of heterocycles. TM-catalyzed alkyne hydroarylations can be classified into three major catego

In the presence of a catalytic amount of Cp*RuCl(cod), 1,6-diynes chemoselectively reacted with monoalkynes at ambient temperature to afford the desired bicyclic benzene derivatives in good yields. A wide variety of diynes and monoynes containing functional groups such as ester, ketone, nitrile, amine, alcohol, sulfide, etc. can be used for the present ruthenium catalysis. The most significant advantage of this protocol is that the cycloaddition of unsymmetrical 1,6-diynes with one internal alky

In the presence of a catalytic amount of Cp*RuCl(cod), 1,6-diynes were allowed to react chemo- and regioselectively with electron-deficient nitriles and heterocumulenes at 60-90 degrees C to afford heterocyclic compounds. The mechanism of the ruthenium-catalyzed regioselective formations of bicyclic pyridines and pyridones were analyzed on the basis of density functional calculations. Cyclocotrimerizations of ethyl propiolate with ethyl cyanoformate or propyl isocyanate gave rise to two of the f

Transition-metal-catalyzed or -mediated intramolecular [2 + 2 + 2] alkyne cyclotrimerizations are one of the most efficient method to construct highly substituted arene frameworks in a single operation. The recent developments of novel catalyst systems as well as new strategies render the intramolecular cyclotrimerizations more and more attractive tools in practical organic synthesis. This review surveys most recent research works on the intramolecular alkyne cyclotrimerizations published from 2

ADVERTISEMENT RETURN TO ISSUEPREVReviewNEXTSilver-Catalyzed Csp−H and Csp−Si Bond Transformations and Related ProcessesYoshihiko Yamamoto*View Author Information Department of Applied Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology, Ookatyama, Meguro-ku, Tokyo 152-8552, Japan* E-mail: [email protected]Cite this: Chem. Rev. 2008, 108, 8, 3199–3222Publication Date (Web):July 9, 2008Publication History Received6 February 2008Published online9 July 2008Published

CuBr2-catalyzed three-component coupling of N-benzylallylamine, ethyl glyoxalate, and terminal alkynes afforded glycine-tethered 1,6-enynes, which were further transformed into polycyclic pyrrole-2-carboxylates via novel cycloisomerization/Diels-Alder cycloaddition/dehydrogenation sequence under iridium-catalyzed conditions.

ADVERTISEMENT RETURN TO ISSUEPREVReviewNEXTTransition-Metal-Catalyzed Cycloisomerizations of α,ω-DienesYoshihiko Yamamoto*View Author Information Department of Basic Medicinal Sciences, Graduate School of Pharmaceutical Sciences, Nagoya University, Chikusa, Nagoya 464-8601, Japan*E-mail: [email protected]Cite this: Chem. Rev. 2012, 112, 8, 4736–4769Publication Date (Web):June 15, 2012Publication History Received9 February 2012Published online15 June 2012Published inissue 8 August 2012https://pub

The Ru(II)-catalyzed [2+2+2] cyclotrimerization of alkynylboronates, propargyl alcohol, and terminal alkynes proceeded chemo- and regioselectively to give rise to arylboronates, which were subjected to Suzuki-Miyaura cross-coupling with aryliodides to afford highly substituted biaryls in 53-76% yields.

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTSignificant Chemo- and Regioselectivies in the Ru(II)-Catalyzed [2 + 2 + 2] Cycloaddition of 1,6-Diynes with DicyanidesYoshihiko Yamamoto, Ryuji Ogawa, and Kenji ItohView Author Information Department of Molecular Design and Engineering Graduate School of Engineering, Nagoya University Chikusa, Nagoya 464-8603, Japan Cite this: J. Am. Chem. Soc. 2001, 123, 25, 6189–6190Publication Date (Web):June 2, 2001Publication History Received7 November 2000

Highly substituted phthalides were efficiently synthesized by sequential Cp(*)RuCl-catalyzed cyclotrimerization of alkynylboronates, propargyl alcohols, and terminal alkynes and palladium(II)-catalyzed carbonylation of the resultant arylboronates. The intermediate arylboronate was isolated and unambiguously characterized by X-ray crystallography. The perfect regioselectivity of the ruthenium-catalyzed formal intermolecular cyclotrimerization was discussed on the basis of the density functional c

In the presence of a catalytic amount of [Cp*RuCl(cod)] (Cp*=pentamethylcyclopentadienyl, cod=1,5-cyclooctadiene), 1,6-diynes were allowed to react chemo- and regioselectively with nitriles bearing a coordinating group, such as dicyanides or alpha-halonitriles, at ambient temperature to afford bicyclic pyridines. Careful screening of nitrile components revealed that a C[triple chemical bond]C triple bond or heteroatom substituents, such as methoxy and methylthio groups, proved to act as the coor

[reaction: see text] A ruthenium(II) complex possessing a planar Cp ligand, CpRu(cod)Cl, effectively catalyzed the [2 + 2 + 2] cycloaddition of 1,6-diynes with isocyanates to afford bicyclic pyridones in 58-87% yields.

The CuOAc-catalyzed reaction of internal alkynoates with arylboronic acids proceeded under mild conditions to yield trisubstituted cinnamates stereoselectively.

The ruthenium(II)-catalyzed tandem cycloaddition of 1,6-heptadiynes with bicyclic alkenes, such as bicyclo[3.2.1]heptenones and norbornene derivatives, furnishes the 1:2 adducts between the diynes and two molecules of the bicycloalkenes together with common [2 + 2 + 2] cyclocotrimerization products. The structure of a representative tandem 1:2 adduct between dimethyl dipropargylmalonate and 2,4-dimethylbicyclo[3.2.1]oct-6-en-3-one was unequivocally determined by X-ray analysis and was concluded

In the presence of 2-4 mol % of CuOAc, methyl phenylpropiolates having a MOM-protected hydroxy group at the ortho position underwent hydroarylation with various arylboronic acids in MeOH at ambient temperature, resulting in the formation of 4-arylcoumarins in high yields after the acidic workup. This method was effectively used for the synthesis of biologically active natural and artificial compounds.