My PhD dissertation - Institut Fresnel

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62 48. This experimental result could once more be explained by possible lithium-oxygen coordination, forcing the biphenyl unit to adopt a rigid twisted conformation, similarly as would a carbon-bridge do. A full lineshape analysis was also performed on dilithiobiphenyl 49 [211] (Figure 9) and Eyring plot of the rate constant obtained (Graphic 1), revealed an activation enthalpy of ∆ = ≠ H 15.1 kcal·mol -1 and entropy of ∆ = 0.2 cal·mol ≠ -1 -1 S ·K (R² = 0.9655). It should be noticed that an extremely accurate lineshape fitting was best achieved at high temperature since shim at very low temperature (-50 °C) was tedious and rendered the spectrum base line "noisy" to some extent. The low value of entropy found by calculation also helped to confirm that the rotational isomerisation of the dilithiobiphenyl considered occurs as a monomolecular phenomenon. The activation free enthalpy experimentally determined should thus be devoid of aggregation factors. ln(k/T) 25 20 15 10 5 0 -5 -10 -15 Li O 49 Li O y = -7,6208x + 23,84 R 2 = 0,9655 0 1 2 3 4 5 1000/T Graphic 1. Eyring plot ln(k/T) = f(1000/T) determined from the full lineshape analysis of dilithiobiphenyl 49.
63 Figure 9. Full lineshape analysis of dilithiobiphenyl 49: experimental spectra at various temperature (left) and corresponding rate constant for simulated spectra (left).
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Various Facets of Organophosphorus
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III Remerciements Je tiens à remer
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3.3.6 Relevance of the Data Assesse
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VII Literature References 115 Compo
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IX Version Abrégée Les composés
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1 Introduction 1 The present thesis
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3 research groups in the field are
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5 However, this mechanism suffers f
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7 At first, a double bromine/lithiu
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10 Although the most frequently emp
Page 32 and 33: 12 The preparation of the latter ph
Page 34 and 35: protected to its dioxolane derivati
Page 36 and 37: N (S)-14 1) NBS, THF, - 75 °C 2) -
Page 39 and 40: 3 Alkaline Decomposition of Phospho
Page 41 and 42: 3.2 Alkyl Carbanions Stabilities in
Page 43 and 44: 3.3.1 Mechanistic Discussion on the
Page 45 and 46: 25 The assumption reported by these
Page 47 and 48: 27 However, in the eventuality of a
Page 49 and 50: 29 To prepare tertiary phosphines b
Page 51 and 52: 31 Table 4. Mixed tertiary alkylpho
Page 53 and 54: 33 were comparable to those obtaine
Page 55 and 56: 35 led to the formation of di-tert-
Page 57 and 58: 37 depending on the alkyl substitue
Page 59 and 60: 39 4 A Novel Access to Atropisomeri
Page 61 and 62: 41 Since the homocoupling of the ha
Page 63 and 64: 43 Few other attempts to selectivel
Page 65 and 66: 45 The second phenol ether 36 was f
Page 67 and 68: 47 The enantiomeric purity was chec
Page 69 and 70: 49 A second purpose of this derivat
Page 71 and 72: 51 substrates considered. In conseq
Page 73 and 74: 53 Single-crystal X-ray analysis of
Page 75 and 76: 55 To convert atropisomer Ia into I
Page 77 and 78: 57 This finally allows one to use t
Page 79 and 80: the steric bulk and charge delocali
Page 81: 61 To check the reproducibility of
Page 86 and 87: 66 suitably substituted dilithiobip
Page 89: Experimental Part
Page 92 and 93: 70 deuterochloroform (CDCl3) unless
Page 94 and 95: 72 1 H NMR: δ = 7.32 (dddd, J = 9,
Page 96 and 97: 1 H NMR: δ = 6.96 (s, 3 H), 6.94 (
Page 98 and 99: 76 C21H21O9P (448.36) calcd. C 56.2
Page 100 and 101: 78 C12H12BrN (250.13) calcd. C 57.6
Page 102 and 103: 80 C13H13NO2 (215.25) calcd. C 72.5
Page 104 and 105: 82 3.1.1 Dialkyl-N,N-diethylaminoph
Page 106 and 107: 84 apparatus. The solution was adde
Page 108 and 109: 86 Di-tert-butylisopropylphosphine
Page 110 and 111: 88 13 C NMR: δ = 32.9 (d, J = 12 H
Page 112 and 113: 90 13 C NMR: δ = 41.5 (d, J = 61 H
Page 114 and 115: 31 P NMR: δ = 53.4 ppm. 92 C16H31O
Page 116 and 117: 94 13 C NMR: δ = 40.8 (d, J = 3 Hz
Page 118 and 119: 96 31 P NMR settings: It is known t
Page 120 and 121: 98 Theoretical ratio: (96.1:3.9) Ex
Page 123 and 124: 101 4 The Preparation and Racemate
Page 125 and 126: 103 extraction protocol with ethyl
Page 127 and 128: 105 extracted with ethyl acetate (2
Page 129 and 130: 107 (+)-(M)-Dimethyl-6,6’-dibromo
Page 131 and 132: 109 (+)-(M)-2,2’-Dibromo-6,6’-b
Page 133 and 134:
111 1 H NMR: δ = 7.2 (m, 20 H), 7.
Page 135 and 136:
113 2,2’-Dilithio-6,6’-bis(meth
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References
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116 Conference Proceedings, Naples,
Page 142 and 143:
118 [ 70] J. Drowart, C.E. Myers, R
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120 [117] S.T. Graul, R.R. Squires,
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122 [170] B.H. Lipshutz, F. Kayser,
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124 [212] M. Schlosser, in Organome
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O P 27i: p. 30, 80 C 9H 21OP P 26b:
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P P P O 2: p. 11, 59 3 P O O O 11:
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Nom Maurin Prénom Michaël 129 Cur
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