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Highly substituted iodobenzenes were efficiently and regioselectively synthesized from readily available 1,6-diynes through two-step process consisting of silver-catalyzed Csp-H iodination and subsequent ruthenium-catalyzed cycloaddition of resultant iododiynes. One of the obtained p-diiodobenzenes was utilized as a halide component for cross-coupling reactions such as Mizoroki-Heck reaction, Sonogashira reaction, and Suzuki-Miyaura coupling.

Cp*RuCl-catalyzed cycloadditions of alpha, omega-diynes with electron-deficient carbon-heteroatom multiple bonds results in various heterocyclic compounds with significant chemo- and regioselectivity. The regiochemistry of these cycloadditions was successfully controlled by the steric and electronic influence of the unsymmetrical diyne substrates.

Palladium(O)-catalyzed cyclodimerization and cycloisomerizations of enyne esters is described. Uncommon six-membered ring products were predominantly formed with concomitant enyne metathesis products when enyne esters bearing a methallyl moiety were used.

A novel four-component coupling strategy is explored to synthesize polycyclic pyrrole-2-carbohydrates. The approach comprises the relay process of the Cu-catalyzed three-component condensation giving rise to glycinate-tethered 1,6-enynes and the subsequent Ir-catalyzed cycloisomerization/Diles-Alder cycloaddition/dehydrogenative aromatization.

Highly substituted phthalides are 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 perfect regioselectivity of the ruthenium-catalyzed formal intermolecular cyclotrimerization is discussed on the basis of the density functional calculations of a boraruthenacycle intermediate.

A new efficient catalytic system for the highly anti-selective and enantioselective reductive aldol reaction of acrylates and aldehydes with hydrosilanes is found. It is found that Rh(Phebox) complexes act as efficient catalysts for the asymmetric conjugate reduction of alpha, beta-unsaturated esters with several hydrosilanes.

The chemo-and regioselective catalytic cyclomerization of unsymmetrical three alkyne components, by means of the temporary tethering approach with ruthenium catalysis is reported. The catalytic intermolecular cyclotrimerization of three different unsymmetrical alkynes can be accomplished with the help of ruthenium catalysis.

Conceptually new bifunctional chiral ligands were developed. The axially chiral N,N-bidentate phenanthroline ligand (S)-1 was found to be effective for Pd-catalyzed asymmetric allylic substitution of allyl acetate and dialkyl malonate. The intramolecular Lewis basic group from the hydroxybinaphthyl structure of (S)-1 played a pivotal role in the high reactivity and enantioselectivity. [ABSTRACT FROM AUTHOR]

A square-planar Co4 amide cluster, Co4{N(SiMe3)2}4 ( 2), and an octahedral Co6 hydride cluster, Co6H8(P iPr3)6 ( 4), were obtained from metathesis-type amide to hydride exchange reactions of a CoII amide complex with pinacolborane (HBpin) in the absence/presence of P iPr3. The crystal structure of 4 revealed face-capping hydrides on each triangular [Co3] face, while the formal CoII2CoI4 oxidation state of 4 indicated a reduction of the cobalt centers during the assembly process. Cluster 4 catalyzes the hydrosilylation of 2-cyclohexen-1-one favoring the conjugate reduction. Generation of the catalytically reactive Co cluster species was indicated by a trapping experiment with a chiral chelating agent. [ABSTRACT FROM AUTHOR]

In the field of asymmetric synthesis, the development of new chiral ligands has been regarded as an attractive challenge for decades. Novel chiral ligands can often have a great impact on synthetic protocols. In this context, we are currently interested in the application of 1,10-phenanthroline (phen) as an entirely new class of chiral ligand. To handle this issue, we designed a chiral phen ligand that provides the N, N, O-tridentate coordination of the phen moiety and an additional phenolic hydroxyl group. As phen possesses greater coordination ability with various ions, our chiral phen ligand would be valuable as one of the "privileged" chiral ligands applied to a broad range of metal catalysts and new reactions. This account summarizes the results of the application of the chiral phen ligand to various kinds of metal catalysis. [ABSTRACT FROM AUTHOR]

A direct asymmetric alkynylation of ketones with new chiral CCN Rh catalysts containing N-heterocyclic carbene and oxazoline hybrid ligands is described. The catalytic reaction of fluoroalkyl-substituted ketones, ArCOCF2X (X=F, Cl, H), with aromatic and aliphatic alkynes yielded the corresponding chiral propargyl alcohols with high enantioselectivity. Control and kinetic experiments suggested a bis(alkynyl) Rh intermediate as the active species for the C−C bond-forming step. [ABSTRACT FROM AUTHOR]

The enantioselective desymmetrizing conjugate hydrosilylation of prochiral differently γ,γ-disubstituted cyclohexadienone derivatives 2 to furnish the corresponding cyclohexenones 4 with a remote chiral all-carbon quaternary center at the γ position is described. Chiral rhodium-bis(oxazolinyl)phenyl complexes 1 were effective catalysts for this transformation. This catalytic system was extended to the asymmetric transformation of spirocarbocyclic cyclohexadienones 5 to give the corresponding products 6 with high enantiomeric ratios. [ABSTRACT FROM AUTHOR]

Rhodium-catalyzed enantioselective desymmetrizing intramolecular hydrosilylation of symmetrically disubstituted hydrosilanes is described. The original axially chiral phenanthroline ligand ( S)-BinThro (Binol-derived phenanthroline) was found to work as an effective chiral catalyst for this transformation. A chiral silicon stereogenic center is one of the chiral motifs gaining much attention in asymmetric syntheses and the present protocol provides cyclic five-membered organosilanes incorporating chiral silicon centers with high enantioselectivities (up to 91 % ee). The putative active RhI catalyst takes the form of an N, N, O-tridentate coordination complex, as determined by several complementary experiments. [ABSTRACT FROM AUTHOR]

Eine enantioselektive Diborierung von terminalen Alkenen mit chiralem 1 und Bis(pinakolato)dibor (B2pin2) wurde entwickelt. Die anschließende Oxidation des Dibor ‐ Addukts mit Natriumperoxoborat ergab die entsprechenden optisch aktiven 1,2 ‐ Diole mit hohen Ausbeuten und Enantioselektivitäten. [ABSTRACT FROM AUTHOR]

NCN-pincer Ru-complexes containing bis(oxazolinyl)phenyl ligands serve as suitable catalysts in the direct conjugate additions of α,β-unsaturated carbonyl compounds, including ketones, esters, and amides, as well as vinylphosphonates, giving various β-alkynyl carbonyl and phosphonate compounds. A bis(oxazolinyl)phenyl (phebox)-Ru complex also catalyzes the asymmetric conjugate addition of an alkyne with a β-substituted, α,β-unsaturated ketone to produce a chiral β-alkynyl ketone. [ABSTRACT FROM AUTHOR]

Highly efficient and enantioselective hydrosilylation of aromatic alkenes catalyzed by the chiral rhodium acetate complexes with the bis(oxazolinyl)phenyl ligands has been reported that afforded chiral silane derivatives with up to 99% ee. [ABSTRACT FROM AUTHOR]