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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]

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]

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]

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]

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]

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]

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

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]

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]

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]

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]

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]

Abstract: Chiral bis(oxazolinyl)phenyl–rhodium complexes act as catalysts in the combination of AgOTf for direct aldol reaction of ketones and aromatic aldehydes to give the corresponding β-hydroxyketones in high anti-selectivity and a good to high enantioselectivity up to 91% ee. [Copyright &y& Elsevier]

Abstract: Optically active dihydrocinnamate derivatives bearing the chiral carbon center at α-position were synthesized by Rh(Phebox)-catalyzed asymmetric reductive aldol coupling reaction with substituted cinnamates and benzaldehyde derivatives and subsequent dehydroxylation reaction. [Copyright &y& Elsevier]

Abstract: The oxidative addition reactions on 4,5-bis(2-oxazolinyl)-(2,7-di-tert-butyl-9,9-dimethyl)-9H-xanthene (Xabox)/rhodium(I) complex were examined using chloroacetate and substituted diynes to give stereoselectively the corresponding methoxycarbonylmethyl-rhodium(III) complex and rhodacyclopentadiene complexes, respectively. The rhodacycle complex 7 catalyzed the cyclotrimerization of the diynes and alkynes to give arene derivatives. [Copyright &y& Elsevier]

An enantioselective conjugate hydrosilylation of prochiral γ,γ-disubstituted cyclohexadienones furnishes cyclohexenones with a chiral quaternary γ-carbon atom. [ABSTRACT FROM AUTHOR]