Chiral and C2-symmetrical bis(oxazolinylpyridine)rhodium(III) complexes: effective catalysts for asymmetric hydrosilylation of ketones

Nishiyama, Hisao; Sakaguchi, Hisao.; Nakamura, Takashi; Horihata, Mihoko.; Kondo, Manabu; Itoh, Kenji

doi:10.1021/om00105a047

Cited by 406 publications

(128 citation statements)

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“…A comparison of the Rh---C1 and Rh--N distances indicates that the donor atoms of each type have almost equivalent chemical surroundings ( Table 2). The mean Rh--C1 and Rh--N distances in the present complex [2.355 (6) and 2.037 (7).& respectively, with the root mean square deviations given in parentheses] are comparable with those observed in related complexes of Rh III (Acharya, Tavale & Guru Row, 1984;Muir, Ma & Muir, 1989;Nishiyama et al, 1989;Nishiyama, Kondo, Nakamura & Itoh, 1991;Sakaba, Kabuto, Horino & Arai, 1990;Lahuerta, Latorre, Martfnez-M~ez, Garcfa-Granda & Gtmez-Beltr~in, 1991;Ma, Li, Muir & Muir, 1993). In the title complex, any two N atoms form a basal plane with two of the C1-ions.…”

Section: Ci/ X Ci (I)supporting

confidence: 80%

Trichloro[tris(2-pyridyl)methanol]rhodium(III)–Methanol (1/1)

Ertan¹,

Adolfsson²,

Moberg³

1995

Acta Crystallogr C

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(2) 161 (4) Symmetry codes: (i) 2 -x, 1 -y, 1 -z; (ii) 1 -x, 2 -y, 2 -z.Data collection used 20 scan rates of 5.33 (Ip < 150) to 58.6 ° min -I (Ip > 2500), where Ip is the prescan intensity. Scan widths were 2.4 to 2.8 ° (20). Refinement was by full-matrix least squares. All non-H atoms were refined anisotropically. The initial positions of hydroxyl H atoms were determined by rigid-body refinement of O-centred 'methyl' groups, each with two dummy H atoms having zero siteoccupancy factors, and then refined in the usual manner but with a common group Uiso. Methylene H atoms were placed in calculated positions (C--H 0.95/~) and refined riding on the C atom to which they were attached with a second common group Uiso. All computations were performed on the SUN SPARCserver (UNIX operating system) of the Computing Centre of the University of Aberdeen.Data reduction: RDNIC (Howie, 1980 AbstractAn X-ray diffraction study of [Rh{ (C5I-hN)3COH}C13].-CH3OH showed that the tris(2-pyridyl)methanol ligand coordinates to the Rh atom in a tridentate fashion, with the N atoms positioned at three comers of an octahedron

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Section: Ci/ X Ci (I)supporting

confidence: 80%

Trichloro[tris(2-pyridyl)methanol]rhodium(III)–Methanol (1/1)

Ertan¹,

Adolfsson²,

Moberg³

1995

Acta Crystallogr C

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“…were first used as catalyst precursors by Nishiyama and co-workers in the enantioselective synthesis of secondary alcohols by the asymmetric reduction of ketones with diphenylsilane. [10] (Scheme 5). They assumed the formation of a rhodium(i) complex as the active species in situ by reduction of the precatalyst in the presence of AgBF 4 and diphenylsilane.…”

Section: Hydrosilylation Of Acetophenonementioning

confidence: 99%

Novel Carbonyliridium and ‐rhodium Complexes Containing 2,6‐Bis[(4′S)‐4′‐isopropyloxazolin‐2′‐yl]pyridine (iPr‐pybox) and 2,6‐Bis[(4′R)‐4′‐phenyloxazolin‐2′‐yl]pyridine (Ph‐pybox) Ligands

et al. 2006

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“…The preparation of enantiomerically pure secondary alcohols is of special significance because these intermediates constitute valuable building blocks for the manufacture of pharmaceuticals, agrochemicals, and advanced materials.[1] Catalytic asymmetric hydrogenation of prochiral ketones is the most direct route to optically active alcohols, [2] however, hydrosilylation of carbon-carbon and carbonheteroatom bonds is a promising alternative to asymmetric hydrogenation because of the mild conditions and operational simplicity.[3]The earliest reports on hydrosilylation appeared three decades ago, [4] and known asymmetric hydrosilylations of prochiral ketones rely on precious metals such as rhodium, [5] ruthenium, [6] and iridium. [7] Less expensive metals such as titanium, [8] zinc, [9] tin, [10] and copper [11] have also been explored.…”

mentioning

confidence: 99%

Iron‐Catalyzed Enantioselective Hydrosilylation of Ketones

2008

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Dedicated to Professor Wolfgang A. Herrmann on the occasion of his 60th birthday Noteworthy efforts have been devoted to the development of efficient catalytic asymmetric reductions employing benign and environmentally available biometals such as iron, zinc, and copper. The preparation of enantiomerically pure secondary alcohols is of special significance because these intermediates constitute valuable building blocks for the manufacture of pharmaceuticals, agrochemicals, and advanced materials.[1] Catalytic asymmetric hydrogenation of prochiral ketones is the most direct route to optically active alcohols, [2] however, hydrosilylation of carbon-carbon and carbonheteroatom bonds is a promising alternative to asymmetric hydrogenation because of the mild conditions and operational simplicity.[3]The earliest reports on hydrosilylation appeared three decades ago, [4] and known asymmetric hydrosilylations of prochiral ketones rely on precious metals such as rhodium, [5] ruthenium, [6] and iridium. [7] Less expensive metals such as titanium, [8] zinc, [9] tin, [10] and copper [11] have also been explored. Each method has its virtues as well as its limitations. The limitations include either the cost of the metal catalyst, the toxicity of the residual metal in the product, the operational difficulties (e.g. low temperatures ranging from À50 to À70 8C), or the use of complex ligand systems.Recently, we started a program to develop more sustainable catalysts by replacing precious metals with nonprecious metals. In accord with the concept of "cheap metals for noble tasks", [12] the possible uses of iron catalysts are especially attractive.[13] Iron is the second most abundant metal available and plays an important role in biology.[14] Despite the many advantages and recent attention [15] to iron catalysis, it remains undeveloped compared to other transition metals (e.g. Ru, Rh, Pd, and Ir etc.), particularly in the field of asymmetric catalysis. To the best of our knowledge there is only one report by Nishiyama ând Furuta [16] on the development of iron-catalyzed asymmetric hydrosilylation. They used multidentate nitrogen ligands and reported enantioselectivities of up to 79 %. The scope of this work can be expanded; herein, we disclose our results on an improved and general ironcatalyzed asymmetric hydrosilylation of ketones (Table 1).Our recent study on the hydrosilylation of aldehydes revealed that Fe(OAc) 2 in the presence of electron-rich phosphine ligands and hydrosilanes forms an active catalyst.[17] On the basis of these findings we turned our attention to the asymmetric reduction of ketones.Initially, several chiral ligands were tested for the reduction of acetophenone to 1-phenylethanol by using a given set of conditions and selected phosphines (Table 1 and Figure 1). Privileged ligands such as (S)-2,2'-bis(diphenyl-, (S,S)-l-benzyl-3,4-bis-(diphenylphosphino)pyrrolidine ((S,S)-deguphos), and binaphthyl derived systems, such as L1 and L2, gave good to excellent conversions of acetophenone (68-99 %), but poor enan...

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Chiral and C2-symmetrical bis(oxazolinylpyridine)rhodium(III) complexes: effective catalysts for asymmetric hydrosilylation of ketones

Cited by 406 publications

References 0 publications

Trichloro[tris(2-pyridyl)methanol]rhodium(III)–Methanol (1/1)

Trichloro[tris(2-pyridyl)methanol]rhodium(III)–Methanol (1/1)

Novel Carbonyliridium and ‐rhodium Complexes Containing 2,6‐Bis[(4′S)‐4′‐isopropyloxazolin‐2′‐yl]pyridine (iPr‐pybox) and 2,6‐Bis[(4′R)‐4′‐phenyloxazolin‐2′‐yl]pyridine (Ph‐pybox) Ligands

Iron‐Catalyzed Enantioselective Hydrosilylation of Ketones

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