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CHEMTECH
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24
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84989560679
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The activation of a stoichiometric reagent by a ligand is considered as “ligand acceleration”. To be a ligand‐accelerated catalysis (LAC) a catalytically active species (other than the ligand) must be present.
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25
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37049083405
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For a very well studied example of a ligand‐accelerated stereoselective reaction, see, J. Chem. Soc. Perkin Trans 2
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(1993)
, pp. 1409
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Klute, W.1
Dress, R.2
Hoffmann, R.W.3
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Mashima, K.1
Kusano, K.2
Sato, N.3
Matsumura, Y.4
Nozaki, K.5
Kumobayashi, H.6
Sayo, N.7
Hori, Y.8
Ishizaki, T.9
Akutagawa, S.10
Takaya, H.11
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48
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84989508450
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If the in situ self‐assembly leads to more than one catalytically active chiral species, cooperative or counteracting stereochemical effects may result. Even in the worst cases, ligand acceleration can enable the desired transformation to occur in a rapid and highly stereoselective manner.
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77
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0002098511
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Katalytische und stöchiometrische enantioselektive Additionen von Diethylzink an Aldehyde mit Hilfe eines neuartigen chiralen Spirotitanats
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Angewandte Chemie
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Schmidt, B.1
Seebach, D.2
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81
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0000233048
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2,2-Dimethyl-α,α,α′,α′-tetra(naphth-2-yl)-1,3-dioxolan-4,5-dimethanol (DINOL) für die Titanat-vermittelte, enantioselektive Addition von Diethylzink an Aldehyde
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(1991)
Angewandte Chemie
, vol.103
, pp. 1383
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Schmidt, B.1
Seebach, D.2
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83
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0000389195
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On the Mechanisms of Enantioselective Reactions Using ?,?,??,?? -Tetraaryl-1,3-dioxolane-4,5-dimethanol(TADDOL)-Derived Titanates: Differences betweenC2- andC1-symmetrical TADDOLs - facts, implications and generalizations
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(1992)
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Seebach, D.1
Plattner, D.A.2
Beck, A.K.3
Wang, Y.M.4
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Pettner, W.6
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88
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0010342137
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Enantioselektive katalytische Addition funktionalisierter Dialkylzinkverbindungen an β-stannylierte Aldehyde; eine einfache Methode zur Herstellung nichtracemischer β- und γ-funktionalisierter sekundärer Alkohole
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, pp. 629
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Brieden, W.1
Ostwald, R.2
Knochel, P.3
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98
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84989597783
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The normal catalyst loadings are 8 mol% for the additions of the functionalized organozinc complexes [30a–g].
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101
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84989561738
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3 catalyzed by titanium/tartrate mixtures. The complex derived from di‐tert‐butyltartrate ester effected enantioselective catalysis, whereas the catalyst prepared with the diisopropyl ester was only effective under stoichiometric conditions:, Synlett
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(1991)
, pp. 774
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Hayashi, M.1
Kohmura, K.2
Oguni, N.3
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102
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0001039136
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4], in stoichiometic quantities disrupts the relative rates of exchange between chiral and achiral complexes and has a deleterious effect on ee. Related effects have been noted in the kinetic resolution of allylic alcohols by titanium alkoxide/tartrate mixtures
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(1991)
J. Org. Chem.
, vol.56
, pp. 6966
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McKee, B.H.1
Kalantar, T.H.2
Sharpless, K.B.3
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108
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0001134408
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Katalytische Varianten enantioselektiver C-C-Verknüpfungen: Allylübertragung und Mukaiyama-Aldolreaktion
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(a) For reviews on allylation and related topics, see
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(1994)
Angewandte Chemie
, vol.106
, pp. 433
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Bach, T.1
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118
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84989561712
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University of Utah, unpublished results
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Keck, G.E.1
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119
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84989560608
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Tokyo Institute of Technology, unpublished results.
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Mikami, K.1
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120
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0008767822
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For recent results with a μ‐oxo‐titanium complex, see, J. Chem. Soc. Chem. Commun.
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, pp. 833
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Terada, M.1
Mikami, K.2
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123
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84989597714
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(a) For recent reviews on asymmetric synthesis of cyanohydrins, see:, Synlett
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North, M.1
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128
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84989524957
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(c) J. Chem. Soc. Chem. Commun.
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84989524958
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(e) J. Chem. Soc. Perkin Trans. 1
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0141712450
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(1992)
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Sharpless, K.B.1
Amberg, W.2
Bennani, Y.L.3
Crispino, G.A.4
Hartung, J.5
Jeong, K.‐S.6
Kwong, H.‐L.7
Morikawa, K.8
Wang, Z.‐M.9
Xu, D.10
Zhang, X.‐L.11
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160
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84989512342
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−1 (toluene):, The Scripps Research Institute, unpublished results. Binding constants for the alkaloids DHQ and DHQD are greater in toluene than in tBuOH. The stoichiometric osmylations with bidentate chiral amines [54] are generally run at low temperature in toluene.
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Kolb, H.C.1
Sharpless, K.B.2
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161
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84989512335
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(a) The effect of tertiary amine ligands on the catalytic turnover in the original AD process with NMO as the oxidant in a homogeneous acetone/water system is quite different from that seen in the new two‐phase AD process with potassium hexacyanoferrate(III) as the oxidant. In the NMO system, quinuclidine strongly inhibits the catalysis at concentrations above 0.01 M [5a], and even the alkaloid ligands DHQ and DHQD begin to show inhibition at concentrations greater than 0.5 M [5b]. These effects are probably due to “second‐cycle problems” [5b, 57b], which will not be discussed here since they are absent in the now favored potassium hexacyanoferrate(III)‐based AD system.
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163
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84989524946
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4 loading should be increased to 1 mol%.
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164
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84989524939
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c) for 2‐vinylnaphthalene [55a].
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186
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84989503726
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Dissertation, Massachusetts Institute of Technology, Boston, USA, 1993.
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Kwong, H.‐L.1
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197
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84989504837
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The [3 + 2] mechanism is being examined by a theoretical approach:, University of California, Los Angeles, unpublished results.
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Niwayama, S.1
Houk, K.N.2
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214
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84989504765
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(c) Nippon Kagaku Kaishi
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(1980)
, pp. 670
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215
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84989561690
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(d) Nippon Kagaku Kaishi
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(1982)
, pp. 137
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