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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]

Abstract: A number of transition metal catalysts have been developed for transfer hydrogenation of organic molecules. This method provides a useful process for the reduction of unsaturated molecules without the need for explosive hydrogen gas. An important development in this area is the design of new ligands that improve activity and selectivity under mild reaction conditions. Polydentate ligands are good candidates for producing high performance metal catalysts. This digest describes recent developments in transfer hydrogenation as well as asymmetric reactions using metal catalysts containing polydentate ligand systems. [Copyright &y& Elsevier]

Pin it down: A highly enantioselective diboration of terminal alkenes with chiral 1 and bis(pinacolato)diboron (B2pin2) was realized. Subsequent oxidation of the diboron adducts with sodium peroxoborate readily gave the corresponding optically active 1,2‐diols in high yields and high enantioselectivities. [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]

Transition-metal complexes with a chiral bis(oxazolinyl) phenyl (Phebox) ligand can construct suitable chiral environments around metal centers. Thus far, a number of transition-metal complexes in the range of early to late metals have been prepared via transmetalation, cyclometalation, and oxidative addition. The fundamental properties and catalytic activities of the resulting Phebox complexes have been extensively investigated. In particular, the Phebox-Rh and Phebox-Ru complexes were found to serve as efficient and selective catalysts in asymmetric reactions for carbon-carbon bond formation, reduction of unsaturated bonds, and functionalization reactions. In this Account, we summarize details of the Phebox complexes in terms of preparations, coordination chemistry, and catalytic applications. [ABSTRACT FROM AUTHOR]

Several transition-metal complexes that bind the bis(oxazolinyl)phenyl moiety as a tridentate ligand have been prepared to showcase their highly potent activities for asymmetric catalysis in conjugate reductions, reductive aldol reactions, direct aldol reactions and hydrogenation reactions. Some reactions of the metals were also examined. [ABSTRACT FROM AUTHOR]

Abstract: A combination of a catalyst derived from ferrous acetate and sodium thiophene-2-carboxylate efficiently promoted hydrosilylation of aromatic and aliphatic ketones to give the corresponding secondary alcohols in high yields with extremely high selectivity. [Copyright &y& Elsevier]

Abstract: The conjugate reduction of α,β-unsaturated esters such as acrylates, crotonate, and cinnamates followed by Mannich-type coupling toward aldimines was efficiently promoted by rhodium-bis(oxazolinyl)phenyl catalyst and alkoxyhydrosilanes to show high anti-selectivity up to 99. [Copyright &y& Elsevier]

The article informs that reductive aldol reaction (RA) of unsaturated esters or enones with aldehydes promoted by a catalytic amount of certain transition-metal complexes and stoichiometric hydrosilanes is one of the most promising aldol reaction alternatives, offering an advantage of in situ generation of enolates as nucleophilic condensation counterparts. An impressive extension has been demonstrated with chiral phosphine-rhodium or nitrogen-based ligand-iridium catalysts attaining asymmetric induction accompanied with syn-diastereoselectivity.

Investigates the nonenzymatic kinetic resolution of secondary alcohols. Enantioselective S[sub 2] displacement of hydroxy groups by halogens in the presence of chiral BINAP; Role of enantiopure alcohols for the synthesis of a wide range of natural products, chiral ligands and biologically active compounds.

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]

Review: [95 refs. [ABSTRACT FROM AUTHOR]

The article presents chemical equations for article "Asymmetric Diboration of Terminal Alkenes with a Rhodium Catalyst and Subsequent Oxidation: Enantioselective Synthesis of Optically Active 1,2-Diols" by K. Toribatake and others, published in "Angewandte Chemie International Edition" in 2013.

A cover page of the journal "Angewandte Chemie" is presented.

Review: 72 refs. [ABSTRACT FROM AUTHOR]

Functionalization of a β-C–H bond of a secondary aliphatic amine was accomplished using NCN pincer Rh complex 1 with a chiral bis(oxazolinyl)phenyl ligand. Complex 1 underwent asymmetric alkylation of dicyclopentylamine with CH 2 Cl 2 to form azametallacycle complex 2 . Additionally, the reaction of 1 with triethylamine in CH 2 Cl 2 resulted in the formation of ammonium ylide complex 3 via C–N bond formation. [ABSTRACT FROM AUTHOR]

We describe the preparation and characterizationof new NCN-pincerCo(III) complexes containing bis(oxazolinyl)phenyl (phebox) ligandsas auxiliary ligands. The reaction of Co2(CO)8with the 2-bromo-substituted ligand precursor (phebox-R)Br (1a, R = Me2; 1b, R = iPr) resulted in the formation of the tricarbonyl Co(I)complex (phebox-R)Co(CO)3(2a, R = Me2; 2b, R = iPr), in which NC-bidentatecoordination of the phebox ligand was observed. Complexes 2underwent oxidative addition of I2to give the Co(III)aqua complex (phebox-R)CoI2(H2O) (4a, R = Me2; 4b, R = iPr) by a change in the coordination geometry to the NCN-tridentatemode. Ligand exchange reactions of H2O or I ligand withCNtBu or AgOAc smoothly proceeded to give the isocyanidecomplex (phebox-dm)CoI2(CNtBu) (5) or the acetate complex (phebox-dm)Co(κ1-OAc)(κ2-OAc) (6), respectively. [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]

The coordination of bis(oxazolinyl)phenyl (phebox) ligandsto anFe center was investigated in the reaction of (phebox-R)Fe(CO)2Br (1a: R = Me2; 1b:R = i-Pr) with phosphine and isocyanide compounds.Reaction of 1with an excess amount of PMe3in toluene proceeded at 50 °C to give the corresponding cationiccomplexes [(phebox-R)Fe(CO)(PMe3)2]Br [2a: R = Me2(79%); 2b: R = i-Pr (83%)]. The molecular structures of 2aand 2bwere confirmed by X-ray diffraction analysisthat revealed the pseudo-octahedral geometry with NCN meridional coordinationof the phebox ligand. In contrast, reaction of 1withPMe2Ph gave the neutral phosphine complexes (η2-phebox-R)Fe(CO)(PMe2Ph)2Br [3a: R = Me2(87%); 3b: R = i-Pr (79%)], in which the phebox ligand was coordinated to Fe as anNC bidentate ligand with the oxazoline and phenyl groups. Subsequentreaction of the neutral phosphine complex 3aresultedin the formation of the corresponding cationic complexes [(phebox-Me2)Fe(CO)(PMe2Ph)2]Br (4) viachange in coordination to the tridentate mode. The reactionof 1with tert-butylisocyanide CN(t-Bu) gave a mixture of neutral isocyanide complexes (phebox-Me2)Fe(CO)[CN(t-Bu)]Br (5, 6) in 57 and 10% yields, respectively, viaexchange of one of the CO ligands. Subsequent reaction of 5with CN(t-Bu) resulted in formation ofthe cationic complex {(phebox-Me2)Fe[CN(t-Bu)]3}Br (7a). Similarly, treatment of 1with an excess amount of CN(t-Bu) afforded {(phebox-R)Fe[CN(t-Bu)]3}Br [7a: R = Me2(83%); 7b: R = i-Pr (69%)]. [ABSTRACT FROM AUTHOR]

Carbon–hydrogen bond activation of arenes by thepincerIr(III) acetate complex (phebox)Ir(OAc)2(H2O)(1; phebox = bis(oxazolinyl)phenyl) proceeded at 100°C to give the corresponding aryl Ir(III) complexes (phebox)Ir(Ar)(OAc)in high yields. Reactions of the monosubstituted arenes anisole, toluene,chlorobenzene, acetophenone, and nitrobenzene resulted in the formationof meta- and para-substituted aryl complexes in high yields. Competitiveexperiments between two monosubstituted arenes exhibited relativereaction rates in the order C6H5OMe > C6H5NO2> C6H5COMe> C6H5Cl > C6H5Me.Thekinetic isotope effects of C–H bond activation of benzene andnitrobenzene were determined to be 2.9 ± 0.1 and 2.0 ± 0.4,respectively. The Ir complex 1underwent catalytic borylationof arenes with bis(pinacolato)diboron (B2(pin)2) or pinacolborane (HB(pin)), giving the corresponding borylatedproducts. The Ir complex 1was also reactive toward alkaneC–H bond activation, demonstrated by the reactions with n-heptane and n-octane at 160 °C thatcleanly afforded the corresponding alkyl complexes (phebox)Ir(n-CnH2n)(OAc) (n= 7, 8, respectively). [ABSTRACT FROM AUTHOR]

A novel oxygen-atom-transfer process enables the catalytic [2 + 2 + 1] synthesis of bicyclic furans from α,ω-diynes with DMSO. [CpRu(AN)3]PF6 catalyzed the transfer oxygenative cyclization of diynes with aryl terminal groups, while those of diynes with alkyl terminal groups were effectively promoted by the corresponding Cp* complex. A mechanism for bicyclic furan formation via a ruthenacyclopentatriene was proposed on the basis of both experimental and theoretical studies. [ABSTRACT FROM AUTHOR]

Abstract: The catalytic reductive aldol coupling of 2-phenylpropionaldehyde and acrylate derivatives with rhodium-bisoxazolinyl catalysts resulted in high Felkin–Anh selectivity (β,γ-syn) up to 98% accompanied by α,β-anti diastereoselectivity and high enantiomeric excesses up to 99%. [Copyright &y& Elsevier]

Simple proline-derived anilide-catalyzed asymmetric �intramolecular Michael reaction was described. Chiral cyclic keto-aldehydes were obtained from acyclic formyl enones in excellent yields with good stereoselectivity. The reaction proceeded in exceptionally fast with a commercially available proline anilide. On the other hand, the longer reaction time conduced toward the higher �diastereoselectivity through the favorable isomerization of the cyclic keto-aldehydes. [ABSTRACT FROM AUTHOR]

Highly substituted iodobenzenes were efficiently and regioselectively synthesized from readily available 1,6-diynes via two-step process consisting of silver-catalyzed Csp-H iodination and subsequent ruthenium-catalyzed [2 + 2 + 2] cycloaddition of resultant iododiynes. Some of the obtained iodobenzenes were subjected to palladium-catalyzed C-C bond-forming reactions such as Mizoroki-Heck reaction, Sonogashira reaction, and Suzuki-Miyaura coupling, giving highly conjugated molecules. [ABSTRACT FROM AUTHOR]

Abstract: Chiral palladium and platinum complexes bearing non-symmetrical, PCN pincer ligand, 6-methoxy-3-(4′-isopropyl-2′-oxazolin-2′-yl)phenyl diphenylphosphinite [i-Pr-Phemox-OPPh2], are first synthesized via oxidative addition of (i-Pr-Phemox-OPPh2)Br 6 to Pd2(dba)3 ·(CHCl3) or Pt(dba)2 and subsequent treatment with silver salts. [Copyright &y& Elsevier]

Abstract: The catalytic intermolecular cyclotrimerization of alkynylboronates, propargyl alcohols, and terminal alkynes was accomplished by means of the ruthenium catalysis and the temporary tethering approach with the C–B–O linkage to give rise to highly substituted arylboronates with excellent selectivity. The resultant arylboronates were further converted to highly substituted biaryls via the Suzuki–Miyaura coupling with various aryl iodides using Pd2(dba)3/PCy3 as a catalyst precursor in aqueous toluene. As a consequence, the four-component coupling approach to highly substituted biaryls was successfully established by combining these two operations into a sequential one-pot process. [Copyright &y& Elsevier]

A ruthenium cyclic biscarbene complex reacted with a H2O molecule under mild conditions to produce η5-oxapentadienyl complex, that proved to be the intermediate in the catalytic hydrative cyclization of a diyne. [ABSTRACT FROM AUTHOR]

An abstract of the article "Nickel(II)-Catalyzed Asymmetric Michael Addition of Oxindoles With Modified N,N,O-Tridentate Chiral Phenanthroline Ligands" by Y. Naganawa, H. Abe and H. Nishiyama is presented.

An abstract of the article "Nickel(II)-Catalyzed Asymmetric Michael Addition of Oxindoles with Modified N,N,O-Tridentate Chiral Phenanthroline Ligands" by Yuki Nagawana and colleagues are presented.

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]

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]

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]

Zinc-catalyzed asymmetric α-amination of various cyclic β-ketocarbonyl compounds using azodicarboxylate (II) as the electrophilic nitrogen source is described. [ABSTRACT FROM AUTHOR]

An asymmetric oxygen atom transfer of oxindole derivatives using Davis′ oxaziridine gives the corresponding 3-aryl-3-hydroxy-2-oxindole derivatives with excellent enantioselectivity. [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]

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]

The catalytic intermolecular cyclotrimerization of three different unsymmetrical alkynes was accomplished by means of the ruthenium catalysis and the temporary tethering approach with the C-B-O linkage. The crude arylboronates were further applied to the Suzuki-Miyaura coupling with various aryl iodides using Pd2(dba)3/PCy3 as a catalyst precursor in aqueous toluene to afford biaryls. As a result, the novel four-component coupling approach to highly substituted biaryls was successfully established by combining these two operations into a sequential one-pot process.

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]

Asymmetric diboration of N -acyl-protected allylamines such as substituted imides, amides, and carbamates catalyzed by chiral rhodium[bis(oxazolinyl)phenyl] complexes followed by oxidation in one-pot was realized to produce optically active 3-amino-1,2-propanediol derivatives in high enantioselectivities up to 99%. [ABSTRACT FROM AUTHOR]

A chiral NCN-pincer Ru-complex serves as suitable catalyst in the conjugate addition of alkynes with α,β-unsaturated ketones, esters, and amides, as well as vinylphosphonates. [ABSTRACT FROM AUTHOR]

Generally, a broad spectrum of bicyclic furan skeletons can be obtained from diynes bearing 2 terminal aryl substituents under the optimized conditions A)-C). [ABSTRACT FROM AUTHOR]

Abstract: Chiral rhodium[bis(oxazolinyl)phenyl] complexes exhibited high catalytic activity for the β-boration of α,β-unsaturated esters, ketones, and amides with bis(pinacolato)diboron in the presence of sodium tert-butoxide to attain high enantioselectivity of up to 97%. The substrate scope and catalytic mechanism were discussed. [Copyright &y& Elsevier]

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]

Conjugate hydrosilylation of 3,3-diarylacrylate derivatives catalyzed by chiral rhodium-bis(oxazolinyl)phenyl complexes (1 mol %) at 60 °C for 2 h was investigated to prepare optically active 3,3-diarylpropanoate derivatives in high yields up to 99% yield and high enantioselectivities up to 99%. [ABSTRACT FROM AUTHOR]

Conjugate allylation of a variety of electron-deficient alkynes with allylboronate (II) proceeds smoothly in the presence of Cu(II) catalyst to afford 1,4-dienes, e.g. (III) or (VIII), in high yields. [ABSTRACT FROM AUTHOR]

The chiral bulky (9-anthracenyl)ethanol enhances the enantioselectivities up to 50% in the asymmetric hydrogenation of prochiral ketones, even in protic solvents. [ABSTRACT FROM AUTHOR]

Bis(oxazolinyl)phenylrhodium(III) aqua complexes, (Phebox)RhX2(H2O) [X = Cl, Br], were found to be efficient Lewis acid catalysts for the enantioselective addition of allyl- and methallyltributyltin reagents to amino aldehydes. The reactions proceed smoothly in the presence of 5-10 mol % of (Phebox)RhX2(H2O) complex at ambient temperature to give the corresponding amino alcohols with modest to good enantioselectivity (up to 94% ee). [ABSTRACT FROM AUTHOR]

Zinc acetate proved to be an efficient catalyst for hydro�silylation of ketones and aldehydes in the combination with (EtO)2MeSiH, and a good to excellent asymmetric induction was observed in the presence of chiral N2S2 ligands. [ABSTRACT FROM AUTHOR]