Kazushi Mashima

Synthesis of partially hydrogenated BINAP variants

Abstract Three pairs of new axially dissymmetric diphosphine ligands, (R)-(−)- and (S)-(+)-2,2′-bis(dicyclohexyl-phosphino)-1,1′-binaphthyl [(R)-(−)- and (S)-(+)-Cy-BINAP], (R)-(+)- and (S)-(−)-2,2′-bis(diphenylphosphino)-5,5′,-6,6′,7,7′,8,8′-octahydro-1,1′-binaphthyl [(R)-(+)- and (S)-(−)-H 8 -BINAP], and (R)-(−)- and (S)-(+)-2,2′-bis(dicyclohexyl-phosphino)-5,5′,6,6′,7,7′,8,8′-octahydro-1,1′-binaphthyl [(R)-(−)- and (S)-(+)-Cy-H 8 -BINAP], have been synthesized and their absolute configurations have been determined on the basis of an X-ray analysis and CD spectra.

Asymmetric hydroformylation of vinyl acetate by use of chiral bis(triarylphosphite)-rhodium(I) complexes

Abstract Bis(triarylphosphite) ligands 1–4 were prepared in optically pure forms from (R)- or (S)-binaphthol and (ArO) 2 PCl, and their Rh(I) complexes have been used as catalysis for hydroformylation of vinyl acetate. The corresponding branched aldehyde, 2-acetoxypropanal, was given in up to 95% regioselectivity and in 49% ee.

Highly stereoselective asymmetric hydrogenation of 2-benzamidomethyl-3-oxobutanoate catalysed by cationic binap–ruthenium(II) complexes

Highly diastereoselective hydrogenation of methyl 2-benzamidomethyl-3-oxobutanoate has been accomplished by using [Rul{(R)-binap}(p-cymene)]I and corresponding complexes of derivatives of binap as catalyst, giving methyl (2S,3R)-2-benzamidomethyl-3-hydroxybutanoate, a versatile intermediate for the synthesis of β-lactam antibiotics, in up to 98% diastereoisomeric excess and 99% enantiomeric excess.

Synthesis of partially hydrogenated 2,2′-bis(diphenylphosphenyl)-1,1′-binaphthyl (BINAP) ligands and their application to catalytic asymmetric hydrogenation

Three pairs of new axially dissymmetric bisphosphane ligands, (R)-(–)- and (S)-(+)-2,2′-bis(dicyclohexylphosphanyl)-1,1′-binaphthyl [(R)-(–)-and (S)-(+)-Cy-BINAP, (R)-(–)-and (S)-(+)2], (R)-(+)- and (S)-(–)-2,2′-bis(diphenylphosphanyl)-5,5′,6, 6′,7,7′,8,8′-octahydro-1,1′-binaphthyl [(R)-(+)- and (S)-(–)-H8-BINAP, (R)-(+)- and (S)-(–)-3], and (R)-(–)- and (S)-(+)2,2′-bis(dicyclohexylphosphanyl)-5,5′,6,6′,7,7′, 8,8′-octahydro-1,1′-binaphthyl [(R)-(–)- and (S)(+)-Cy-H8-BINAP, (R)-(–)- and (S)-(+)-4], have been synthesized. The absolute configurations of the isomers 2 were determined by single-crystal X-ray diffraction of the linear 1:1 polymeric complex of (S)-(+)-2,2′-bis(dicyclohexylphosphinoyl)-1,1′-binaphthyl [(S)-(+)-Cy-BINAPO, (S)(+)-6] and (2R, 3R)-(–)-di-O-benzoyltartaric acid [(–)-DBT], and those of the isomers 3 and 4 were established on the basis of CD spectra of the phosphanes and their bisoxides. X-Ray crystallographic studies of two cationic RhI complexes, [Rh{(S)-Cy-binap}(cod)]ClO4[(S)-17] and [Rh{(S)-H8-binap}(cod)]ClO4[(S)-18], revealed that complex (S)-17 possesses a dissymmetric structure, while complex (S)-18 has a pseudo-C2-symmetry and shows a significantly large dihedral angle between the two phenyl rings [80.3(4)°]. The potentiality of ligand 3 for asymmetric catalysis was demonstrated in RuII-catalysed stereoselective hydrogenations of methyl 2-(benzamidomethyl)-3-oxobutanoate (21, in up to 92% d.e. and 99% e.e.) and geraniol (22, in 98% optical purity).

Chemoselective asymmetric hydrogenation of α,β-unsaturated carbonyl compounds to allylic alcohols catalysed by [Ir(binap)(cod)]BF4-aminophosphine

Asymmetric hydrogenation of (E)-4-phenyl-3-buten-2-one by use of [Ir(binap)(cod)]BF4 and o-di-methylaminophenyldiphenylphosphine afforded (E)-4-phenyl-3-buten-2-ol in 97% chemoselectivity and in 65% enantiomeric excess. A mixed ligand iridium dihydride complex containing both BINAP and the aminophosphine ligand has been shown to be the catalytically active species.

A new convenient synthesis of cyclooctatetraenyllanthanide complexes: X-ray crystal structure of CeI(C8H8)(THF)3

Abstract Lanthanide metals react with cyclooctatetraene in the presence of iodine to give cyclooctatetraenyliodolanthanide complexes LnI(C8H8)(THF)n (Ln = La, Ce, Pr, Nd, or Sm; n = 1, 2, or 3). The monomeric nature of CeI(C8H8)(THF)3 (1b) is established by a single crystal X -ray analysis. The mechanism of the formation of SmI(C8H8)(THF) (1e) is discussed. A simple one-pot synthesis of LnI(C8H8)(THF)n (Ln = La, Ce, Pr, Nd, or Sm; n = 1, 2, or 3) has been achieved by the reaction of lanthanide metals with cyclooctatetraene in the presence of iodine.

Synthesis and characterization of cationic trinuclear BINAP-Ru(II) complexes : crystal structure of [ru3Cl5((S)-binap)3]BF4

Abstract Treatment of cationic complexes [RuX((S)-binap)(arene)]X (X = Cl, Br; arene = benzene, p-cymene) in methanol at 60 °C or UV irradiation of the solution at room temperature afforded monocationic trinuclear complexes [Ru 3 X 5 ((S)-binap)3]X in 40–62% yields, whose novel structures have been determined based on spectral data, conductivity, and an X-ray crystallographic study

Synthesis of new chiral bis(triarylphosphine) ligands based on asymmetric hydrogenation of 4,5-diaryl-2-oxocyclopentanecarb oxylates

Abstract New chiral bis(triarylphosphine) ligands, trans -bis(3-diphenylphosphinophenyl)cyclopentane and trans -bis(2-diphenylphosphinophenyl)cyclopentane, have been prepared in optically pure forms based on asymmetric hydrogenation of 4,5-diaryl-2-oxocyclopentanecarboxylates catalyzed by the BINAP—Ru(II) complex.

Preparation, structure, and reaction of the tricarbonyliron complex of tricyclo[5.3.1.04,9]undeca-2,5-diene, a strongly homo-conjugated nonparallel 1,4-diene

Abstract Tricarbonyliron complex 3 is prepared by the reaction of a strongly homo-conjugated nonparallel 1,4-diene, tricyclo[5.3.1.0 4,9 ]undeca-2,5-diene ( 2 ), with Fe(CO) 5 or Fe 2 (CO) 9 . Upon complexation a much larger shielding effect (Δδ = 111.8 ppm) of the inner carbons (C3 and C5) than that (Δδ = 73.5 ppm) of the outer ones (C2 and C6) is observed in 13 C NMR of 3 . The chemical shift value of the carbonyl carbons (216.3 ppm) is intermediate between those of tricarbonyliron complexes of norbornadiene ( 1 ) and 1,3-cyclohexadiene. An X-ray crystallographic analysis of 3 reveals that the iron atom is located at almost equal distances from the four olefinic carbons and that the geometry of the iron atom retains a square pyramidal coordination. It also shows that the bond lengths of C3ue5f8C4 and C4ue5f8C5 are relatively short (1.504 and 1.508 A, respectively) and that the bond angle of C3ue5f8C4ue5f8C5 is small (95.1°). Furthermore, the olefinic bonds of 3 are markedly distorted. These results suggest a little contribution of the terminal bonding nature 5 to the overall bonding nature of 3 . Reaction of 3 with aluminum trichloride affords the ring expanded dienone 6 by a carbonyl insertion, showing similarity with that of tricarbonyl(1,3-cyclohexadiene)iron.

Chapter IV.2 New Chiral Rh(I) and Ru(II) Complexes: Highly Efficient Catalysts for Homogeneous Asymmetric Hydrogenation

Abstract Practical methods for the synthesis of ( R )- or ( S )-2,2′-bis(diaryl- or dialkylphosphino)-1,1′-binaphthyls (BINAPs) have been developed. These new axially dissymmetric di- tert -phosphines serve as excellent ligands for Rh(I)—catalyzed asymmetric hydrogenation of α-acylaminoacrylic acids and asymmetric isomerization of allylamines to enamines. New mononuclear BINAP—Ru(II) dicarboxylate complexes and cationic BINAP—Ru(II)—arene complexes have also been prepared. These complexes and their derivatives are highly efficient catalysts for asymmetric hydrogenation of enamides, alkyl- and aryl-substituted acrylic acids, β,γ-unsaturated carboxylic acids, allylic and homoallylic alcohols, and a variety of functionalized ketones such as β-keto esters, α-amino ketones, etc .