Tae-Jeong Kim

Ruthenium-catalyzed regioselective α-alkylation of ketones with primary alcohols

Ketones are regioselectively alkylated with an array of primary alcohols in dioxane at 80°C in the presence of a catalytic amount of a ruthenium catalyst together with KOH and a hydrogen acceptor.

Ruthenium-Catalyzed Synthesis of Quinolines from Anilines and Allylammonium Chlorides in an Aqueous Medium via Amine Exchange Reaction

Abstract Anilines react with allylammonium chlorides in an aqueous medium (H2O–dioxane) in the presence of a catalytic amount of RuCl2(PPh3)3 together with SnCl2·2H2O to give the corresponding quinolines in moderate to good yields. The existence of SnCl2·2H2O is necessary for the effective formation of quinolines, and a reaction pathway involving amine exchange reaction between anilines and allylammonium chlorides to form an imine is proposed for this catalytic process.

Ruthenium-catalyzed heteroannulation of anilines with alkanolammonium chlorides leading to indoles

Abstract Anilines react with alkanolammonium chlorides in an aqueous medium (H 2 O–dioxane) at 180°C in the presence of a catalytic amount of a ruthenium catalyst together with SnCl 2 ·2H 2 O to afford the corresponding indoles in moderate to good yields. Especially, when triisopropanolammonium chloride is employed to react with anilines, 2-methylindoles are formed regioselectively. The presence of SnCl 2 ·2H 2 O is necessary for the effective formation of indoles. A reaction pathway involving alkanol group transfer from alkanolamines to anilines, N-alkylation of anilines by anilinoalkanols and heteroannulation of 1,2-dianilinoalkanes is proposed for this catalytic process.

Chiral C2-symmetric bisferrocenyldiamines as ligands for transition metal catalyzed asymmetric cyclopropanation and aziridination

Abstract A new series of chiral C 2 -symmetric bisferrocenyldiimine 1 and bisferrocenyldiamines 2 and 3 proved to be efficient ligands for the copper(I)-catalyzed asymmetric cyclopropanation, cyclopropenation, and aziridination of alkenes and alkynes to give high diastereo- and enantioselectivity as well as high chemical yields. In some instances the enantiomeric excesses of cyclopropanated products are among the highest (>97% ee) ever reported. Comparative studies show that stereoselectivity depends highly on the steric variation both in the ligand and the substrate. Other transition metal complexes incorporating some of these ligands such as Ru( 3c )Cl 2 , [(NBD)Rh( 2 )]ClO 4 , [Cu( 2 )(MeCN) 2 ]PF 6 , and Pd( 2 )Cl 2 also demonstrated high enantioselectivity in cyclopropanation reactions.

Ruthenium-Catalyzed Regioselectiveα-Alkylation of Ketones: The First Alkyl-Group Transfer from Trialkylamines to theα-C Atom of Ketones

A new reaction: A ruthenium-catalyzed transfer of an alkyl group from a trialkylamine to the α-carbon atom of a ketone leads in good yields to α-alkylated ketones [Eq. (1)]. The reaction is applicable to a wide range of alkyl(alkyl), alkyl(aryl), and cyclic ketones, and in the case of unsymmetrical ketones it takes place regioselectively at the less hindered α-position.

Iron complexes of 1,1′-bis(diphenylphosphino)ferrocene (BPPF) as efficient catalysts in the synthesis of carbamates. X-ray crystal structure of (BPPF)Fe(CO)3

Abstract 1,1′-Bis(diphenylphosphino)ferrocene (BPPF) reacts with a 5–10 molar excess of Fe(CO)5 to give three new iron complexes (η2-BPPF)Fe(CO)3 (1), (η1-BPPF)Fe(CO)4 (2), and (μ,η1-BPPF)Fe2(CO)8 (3) with the product distribution depending upon reaction conditions. The structure of 1 has been determined. Crystals are monoclinic, space group P21/c, with a 9.708(1), b 16.195(2), c 19.869(5) A, β 95.75(2)°, V 3108(1) A3, Z = 4, and Dcalc 1.49 g cm−3. The geometry around the central iron is a distorted trigonal bipyramid, with the two phosphorus atoms occupying axial and equatorial positions. All these compounds can catalyze efficiently the reaction of propargyl alcohol with secondary amines in the presence of CO2 to provide corresponding carbamate esters. The yields of some carbamates are among the highest (∼ 65%) ever reported in the literature.

Ruthenium-catalyzed reductive cyclization of nitroarenes with trialkylamines leading to quinolines

Nitroarenes react with trialkylamines in the presence of a catalytic amount of a ruthenium catalyst together with tin(II) chloride dihydrate at 180 °C in an aqueous medium (toluene–H2O) to afford the corresponding quinolines in moderate to good yields. The catalytic pathway seems to be proceeded via a sequence involving initial reduction of nitroarenes to anilines, alkyl group transfer from alkylamines to anilines to form an imine, dimerization of imine, and heterocyclization.

Catalytic formation of carbamates and cyclic carbonates by copper complex of 2,5,19,22-tetraaza[6,6](1,1′)ferrocenophane-1,5-diene X-ray crystal structure of [Cu(1)]PF6

Abstract The reaction of [Cu(MeCN)4]PF6 with a ferrocene-containing tetraazamacrocycle 2,51l9,22-tetraaza[6,6](1,1′)ferrocenophane-1,5-diene (1) gives the copper(I) complex of the type [Cu(1)]PF6 (2) which crystallizes in the orthorhombic system: P212121 (#19); a = 7.597(2) A, b=14.805(5) A, c = 24.194(4) A; Z = 4; R = 0.080; Rw=0.083. The geometry around the central metal is a distorted tetrahedron with two pairs of differing Cu-N bond length. This complex has demonstrated the excellent catalytic activity toward the formation of cyclic carbonates and carbamates in the presence of CO2, giving almost quantitative product yields in most reactions that have been employed.

Palladium-Catalyzed Diastereoselective Synthesis of Isoindolinones

Abstract: 2-Bromobenzaldehyde reacts diastereoselectively with chiral alkanolamines under carbon monoxide in the presence of a catalytic amount of bis(triphenylphosphine)palladium(II) chloride to afford the corresponding tricyclic isoindolinones in moderate to good yields.

Ruthenium-catalyzed regioselective synthesis of 2-substituted indoles via ring-opening of epoxides by anilines

Anilines react with epoxides in dioxane at 180°C in the presence of a catalytic amount of a ruthenium catalyst along with tin(II) chloride to afford 2-substituted indoles in moderate to good yields.