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1
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84985716213
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X‐ray structure analysis.
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6
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84985682510
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[2e], Synthesis
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(1988)
, pp. 645-654
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Brunner, H.1
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17
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0002904790
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[6c]
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(1990)
J. Organomet. Chem.
, vol.382
, pp. 19-37
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Noyori, R.1
Suga, S.2
Kawai, K.3
Okada, S.4
Kitamura, M.5
Oguni, N.6
Hayashi, M.7
Kaneko, T.8
Matsuda, Y.9
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26
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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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[9a]
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(1991)
Angewandte Chemie
, vol.103
, pp. 100-101
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Schmidt, B.1
Seebach, D.2
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30
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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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[9c]
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(1991)
Angewandte Chemie
, vol.103
, pp. 1383-1385
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Schmidt, B.1
Seebach, D.2
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48
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84984360285
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Enantioselektive Addition von Organometallreagentien an Carbonylverbindungen: Übertragung, Vervielfältigung und Verstärkung der Chiralität
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[11a]
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(1991)
Angewandte Chemie
, vol.103
, pp. 34-55
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Noyori, R.1
Kitamura, M.2
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53
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0000980726
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Bis(4,5-dihydrooxazolyl)-Derivate in der asymmetrischen Katalyse
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[12c]
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(1991)
Angewandte Chemie
, vol.103
, pp. 556-558
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Bolm, C.1
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65
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84981869602
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Koordinationschemische Untersuchungen an Zinkdialkylen. VII. Darstellung und Untersuchung von Zinkdialkyl-2,2?-Dipyridyl-Addukten
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[18b]
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(1967)
Z. Anorg. Allg. Chem.
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, pp. 127-134
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Thiele, K.‐H.1
Rau, H.2
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67
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84985697619
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The observation was also made in the vinyl transfer from divinylzinc to aldehydes:, private communication in Basel on October 16, 1991.
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Oppolzer, W.1
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73
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84985706050
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For most substrates the ee value obtained by optical rotation was slightly higher than the one determined by HPLC using a chiral stationary phase or by NMR measurements of the MTPA esters. The latter two methods gave almost identical results (analysis for 2a).
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74
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84985670318
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11b.
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78
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37049082787
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Autocatalysis was also observed in the alkylation of 3‐pyridinecarbaldehyde. Product of low ee was obtained:, J. Chem. Soc., Chem. Commun.
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(1990)
, pp. 982-983
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Soai, K.1
Niwa, S.2
Hori, H.3
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79
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84985640028
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Even in the absence of a catalyst alkylation was observed to give about the same product ratio of 2h and 5. The enantioselectivity of the zinc alkoxide derived from optically active 2h was not examined in detail but it is expected to be lower than that of ( R)‐ 6. The formation of 5 was not inhibited by the presence of 3‐hexyne or p‐benzoquinone which were added to trap a suspected metal hydride intermediate.
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84
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0001269629
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Struktur und Reaktivität von Lithiumenolaten, vom Pinakolon zur selektivenC-Alkylierung von Peptiden – Schwierigkeiten und Möglichkeiten durch komplexe Strukturen
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[34a]
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(1988)
Angewandte Chemie
, vol.100
, pp. 1685-1715
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Seebach, D.1
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95
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0001333978
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In the copper‐catalyzed conjugate addition of Grignard reagents a silylated species is most likely to be involved in the ratedetermining step
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(1990)
Organometallics
, vol.9
, pp. 3178-3181
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Ahn, K.H.1
Lippard, S.J.2
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96
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84985652667
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4 followed by removal of 2‐propanol by azeotropic distillation. Essentially no product was formed after 6 h at –78°C. Stirring for 20 h at room temp. afforded 29% of 2a with 22% ee (HPLC).
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97
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0025079083
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Other unfunctionalized diorganozinc reagents have been successfully applied in amino‐alcohol‐catalyzed reactions: [40a] Diaryl
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(1990)
Helv. Chim. Acta
, vol.73
, pp. 1068-1086
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Hübscher, J.1
Barner, R.2
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98
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37049085863
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[40b] Dialkynyl:, J. Chem. Soc., Perkin Trans. 1
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(1990)
, pp. 937-943
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Niwa, S.1
Soai, K.2
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99
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37049071892
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[40c] Difuryl:, J. Chem. Soc., Perkin Trans. 1
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(1990)
, pp. 3214-3215
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Soai, K.1
Kawase, Y.2
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102
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1542628602
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Highly purified metal homoenolates were reported not to add to carbonyl compounds in the absence of Lewis acids. The zinc homoenolate was particularly difficult to purify: [43a]
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(1985)
J. Org. Chem.
, vol.50
, pp. 2802-2804
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Oshino, H.1
Nakamura, E.2
Kuwajima, I.3
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104
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84985652652
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6.
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106
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84985652654
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11a, footnote 69.
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107
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84985726485
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32. Professor G. van Koten, University of Utrecht, is kindly acknowledged for a stimulating discussion at OMCOS 6.
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116
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0001518262
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Reaction control of guest compounds in host-guest inclusion complexes
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In contrast, for unknown reasons a slight decrease (ca. 1% ee) in optical purity of 2a was observed when the catalyst ee was increased. The formation of inclusion compounds could falsify the determination of the enantiomeric excess, and we attempted to avoid this by careful kugelrphr distillation after the regular workup and purification by column chromatography. For a general description of this phenomenon
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(1988)
Top. Curr. Chem.
, vol.149
, pp. 211-238
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Toda, F.1
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134
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84985674707
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Further details of the crystal structure investigation are available on request from the Fachinformationszentrum Karlsruhe, Gesellschaft für wissenschaftlich‐technische Information mbH, D‐7514 Eggenstein‐Leopoldshafen 2, on quoting the depositor number CSD‐320394, the names of the authors, and the journal citation.
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