My PhD dissertation - Institut Fresnel

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10 Although the most frequently employed method for the preparation of tertiary phosphines i.e. the reaction of phosphorus trihalide with Grignard reagents [ , ] 68 69 or organolithium species [48, 66, 67] is efficient in most cases, this method does not always give satisfactory yields [51] o -1 [ 70 ] . Since the lower reactivity of the P−O bonds ( D298 ≈ 596 kcal·mol ) o compared to the P−Cl bonds ( D 289 kcal·mol 298 ≈ demonstrated by different research groups -1 ) [ ] 71 towards organometallic reagents was [ - ] 72 76 , the use of phosphites instead of phosphorus trichloride was believed to give cleaner reactions and thus, should allow performing reactions on larger scale without any special care. Since the use of phosphorus trichloride was thought to produce, in situ, molecular chlorine and could cause partial oxidation of the phosphine formed, its substitution by a phosphite constituted an additional advantage. As a matter of fact, depending on its structure, the phosphine formed can be prone to rapid oxidation and form, to some extent, the corresponding tertiary phosphine oxide which usually causes tedious purification procedures. Although the use of phosphite for the preparation of tertiary phosphines had already been mentioned in few reports from the beginning of the 20 th century until now [49 - 51, , ] 77 78 , no rational arguments were given to explain the failure of other classical preparation procedures nor the better yields obtained with phosphites. Furthermore, in most cases the yields were relatively low. Therefore, several already described triarylphosphines were prepared by means of triethyl phosphite to evaluate and compare the efficiency of this method compared to more classical ones. Once the "phosphite pathway" procedure had been well established, new furyl and pyrrolylphosphines have been prepared. 2.1 Uniformly Substituted Triarylphosphines Triarylphosphines were formed in excellent yields when triethyl phosphite was condensed with three equivalents of aryllithiums (Table 1). The latter were generated from the corresponding bromoarene by halogen/metal permutation using butyllithium. In the case of tris(3,5-dimethylphenyl)phosphine (7), 1-iodo-3,5-dimethylbenzene material. R X 1) LiC 4H 9, THF, - 75 °C 2) P(OEt) 3, - 75 °C to 25 °C P [ ] 79 served as the starting R 3
11 Table 1. Preparation of variously substituted triarylphosphines 1-4 and 6-7 with triethyl phosphite and aryllithiums generated by halogen/metal permutation of haloarenes Ar−X with butyllithium. H 3CO Aryl phosphine Nr. OCH 3 1 2 N(CH 3) 2 3 4 6 7 X Yield Lit. yield Br Br Br Br Br I The triaryl phosphines 1 - 3, 6 and 7 were obtained in excellent yield (Table 1) and by direct crystallization of the crude reaction product. However, tris(1-naphthyl)phosphine (4) [83] had to be crystallized several times to afford an analytically pure product. As a matter of fact, under the usual reaction conditions, 1 H NMR analysis of the crude reaction mixture revealed the presence of ethylbis(1-naphthyl)phosphinite (5) stemming from incomplete substitution at the phosphorus center. Increased reaction times in refluxing tetrahydrofuran 99% 99% 83% 86% 83% 81% [ ] 80 89% [a] [ ] 81 90% [b] [ ] 82 19% [c] [ ] 83 14% [d] [ ] 84 - [ ] 85 62% [e] [a] Prepared with PCl3 and p-CH3OC6H4MgBr in THF; [b] Prepared with PCl3 and m-CH3OC6H4Li in THF; [c] Prepared with PCl3 and p(CH3)2C6H4MgBr in THF; [d] Prepared with PCl3 and 1-naphthylMgBr in THF; [e] Prepared with PCl3 and 3,5-(CH3)C6H4Li in THF. finally gave the pure phosphine (4) in 86% yield along with only 5% of phosphinite (5). Br 1) LiC 4H9, THF, - 75 °C 2) P(OC 2H5) 3, reflux P 3 + P O 4, 86% 5, 5% 2
Page 1: Various Facets of Organophosphorus
Page 5: III Remerciements Je tiens à remer
Page 9: 3.3.6 Relevance of the Data Assesse
Page 13: VII Literature References 115 Compo
Page 17: IX Version Abrégée Les composés
Page 21 and 22: 1 Introduction 1 The present thesis
Page 23 and 24: 3 research groups in the field are
Page 25 and 26: 5 However, this mechanism suffers f
Page 27: 7 At first, a double bromine/lithiu
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 and 82:
61 To check the reproducibility of
Page 83:
63 Figure 9. Full lineshape analysi
Page 86 and 87:
66 suitably substituted dilithiobip
Page 89:
Experimental Part
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70 deuterochloroform (CDCl3) unless
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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 (
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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
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82 3.1.1 Dialkyl-N,N-diethylaminoph
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84 apparatus. The solution was adde
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86 Di-tert-butylisopropylphosphine
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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
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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
Page 137:
References
Page 140 and 141:
116 Conference Proceedings, Naples,
Page 142 and 143:
118 [ 70] J. Drowart, C.E. Myers, R
Page 144 and 145:
120 [117] S.T. Graul, R.R. Squires,
Page 146 and 147:
122 [170] B.H. Lipshutz, F. Kayser,
Page 148:
124 [212] M. Schlosser, in Organome
Page 152:
O P 27i: p. 30, 80 C 9H 21OP P 26b:
Page 156:
P P P O 2: p. 11, 59 3 P O O O 11:
Page 160:
Nom Maurin Prénom Michaël 129 Cur
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My PhD dissertation - Institut Fresnel

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