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Les travaux rapportés dans ce mémoire concernent la synthèse et la réactivité des disilanes, en vue de leur application vers la synthèse de la 10-silatestostérone. Dans un premier temps, l’intérêt potentiel de la cible choisie, la 10-silatestostérone, a été étayé au moyen d’exemples de molécules d’intérêt biologique présentant un atome de silicium, issus de la littérature. L’objectif de la silasubstitution serait d’empêcher la biotransformation de la molécule en composé aromatique potentiellement cancérigène. Enfin, la substitution en position 10 de l’atome de carbone quaternaire permet d’éviter l’introduction de substituants supplémentaires, susceptibles d’affecter l’activité hormonale de la molécule. Dans un second temps, nous avons optimisés les outils nécessaires à la synthèse de la 10-silatestostérone. Une nouvelle stratégie pour accéder à des disilanes non symétriques a été développée par réaction de déphénylation chlorative. Puis l’étude de la réaction de coupure hétérolytique de la liaison Si-Si de phényldisilanes non symétriques par piégeages des silylures ainsi générés et par une analyse par RMN ¹H a permis de mettre en évidence une sélectivité en faveur du phénylsilylure. Enfin cette réaction a été appliquée pour accéder à des composés carbonylés β-silylés par réaction d’addition-1,4 de silylcuprolithiens sur des composés carbonylés α,β-éthyléniques tels que le cyclohexènecarboxylate de méthyle, un modèle simplifié de l’ester bicyclique que nous envisageons d’utiliser pour apporter la partie C&D de la 10-silatestostérone. Enfin le troisième chapitre porte sur la synthèse des précurseurs de la 10-silatestostérone. Dans une première partie un disilane hautement fonctionnalisé, le 1-isopropényl-1-(3-oxopropyl)disilane a pu être préparé en mettant à profit la réaction de déphénylation chlorative. Puis la réaction ène intramoléculaire de cet aldéhyde a conduit au 1-méthyl-1-triméthylsilyl-2-méthylidène-1-silacyclohexan-4-ol précurseur du cycle A de la 10-silatestostérone ainsi qu’au 1,2-diméthyl-2-triméthylsilyl-1-silacyclohexane-1,4-diol issu d’un réarrangement hautement diastéréosélectif. Dans une seconde partie, est présentée la synthèse énantiosélective de la partie C&D de la 10-silatestostérone par une réaction clé de carboxylation de la dicétone d’Hajos-Parrish. L’étape suivante consistera à réaliser la coupure sélective du disilane porteur du cycle A, et à additionner le silylure ainsi généré sur l’ester α,β-insaturé bicyclique. / This thesis is devoted to the synthesis and the study of the reactivity of disilanes in order to involve them in the 10-silatesosterone synthesis. The first part focuses on the usefulness of 10-silatestosterone by developing some relevant examples, from the literature, of biologically active molecules containing a silicon atom. Thus in the testosterone field, the substitution of a carbon atom by a silicon one is supposed to avoid aromatization of the molecule during its biotransformation. Moreover the 10 position of the silasubstitution prevents from the introduction of new groups, which is known to affect the biological activity of the molecule. In the second part the chemical tools for the 10-silatestosterone synthesis are described. A new strategy has been developed to obtain non symmetrical disilanes by a chlorinative dephenylation sequence. The heterolytic cleavage of the Si-Si bond of non symmetrical phenyldisilanes has been studied by trapping the generated silylanion and by ¹H NMR experiments. Selectivity for the phenylsilylanion formation has been established. Finally this reaction was fully exploited to access to β-silylated carbonyl compounds after 1,4-addition of silylcuprates on α,β-unsaturated carbonyl compounds as methylcyclohexenecarboxylate, model of the C&D rings of 10-silatesosterone. The third part presents the 10-silatestosterone precursors synthesis. At First high functionalized 1-isopropenyl-1-(3-oxopropyl)disilane has been obtained by using the previously performed chlorinative dephenylation reaction. Then intramolecular ene reaction of this aldehyde leads to a mixture of 1-methyl-1-trimethylsilyl-2-methylidene-1-silacyclohexan-4-ol, which corresponds to the 10-silatestosterone A ring and 1,2-dimethyl-2-trimethylsilyl-1-silacyclohexane-1,4-diol coming from diastereoselective rearrangement. Eventually, enantioselective synthesis of 10-silatestosterone C&D rings was achieved through a sequence involving a Hajos-Parrish ketone carboxylation key step. Further work would consist on a selective cleavage of A ring disilane followed by the 1,4-addition of the generated silylanion on α,β-unsaturated bicyclic ester.

Chapter 1.<br />1-Ethynyl-2-phenyltetramethyldisilanes HCºCSiMe2SiMe2C6H4-p-X [X = NMe2(1.1), Me (1.2), H (1.3), Br (1.4), CF3 (1.5)] are accessible from ClSiMe2SiMe2Cl, BrMgC6H4X and HCºCMgBr in a two step Grignard reaction. The crystal structure of 1.1 as determined by single crystal X-ray crystallography exhibits a nearly planar PhNMe2 moiety and an unusual gauche array of the phenyl and the acetylene group with respect to rotation around the Si-Si-bond. Full geometry optimization (B3LYP/6- 31+G**) of the gas phase structures of 1.1 and 1.3 affords minima for the gauche and the trans rotational isomers, both being very close in energy with a rotational barrier of only 3 – 5 kJ/mol. Experimental and calculated (time-dependent DFT B3LYP/TZVP) UV absorption data of 1.1 – 1.5 show pronounced electronic interactions of the HCºC- and the C6H4X p-systems with the central Si-Si bond.<br /><br />Chapter 2.<br />A family of [( 5-Cp*)Ru( 6-arene)]+ (Cp* = C5Me5) sandwich complexes of 1- and 1,4-substituted phenyl and naphthyl systems are described along with the regioselectivities of the reactions under various conditions. Finally, the (h 5-Cp*) Ru+ arenophile was found to act as a gate to the flow of electrons between para-substituted termini. When it is complexed onto the phenyl or A naphthyl ring, the gate is closed. On the contrary, when it is complexed onto the B naphthyl ring, the gate is open.<br /><br />Chapter 3.<br />Regioselective complexation reactions of the organoiron acetylide derivatives (h 2- dppe)(h 5-Cp*)Fe-C C-Ar (Ar = phenyl, 1-naphthyl; dppe = 1,2- bis(diphenylphosphino)ethane) with [(h 5-Cp*Ru(CH3CN)3][PF6] to afford heterobimetallic complexes formulated as [(h 2-dppe)(h 5-Cp*)Fe-C C-{(h 6-Ar)Ru(h 5- Cp*)}][PF6], were achieved. In the case of the FeII-RuII 1-naphthyl derivative, the (h 5-Cp*)Ru+ arenophile was complexed both onto the substituted ring and free rings of the acetylide 1-naphthyl linker. The first redox-driven h 6-h 6 inter-ring haptotropic migration of the (h 5-Cp*)Ru+ moeity was shown to occur. Crystal structures of all of the seven new iron acetylenes were resolved, including both haptotropomers of the naphthyl compound.<br /><br />Chapter 4.<br />The diorganoiron [{(h2-dpppe)(h5-Cp*)Fe-CC-}2(1,4-naphthyl)] (4.12) was synthesized in good yield in two steps via the vinylidene, and oxidation led to the mixed valence (MV) and iron(III)-iron(III) species in good to excellent yields. This exhaustive empirical study on the family of complexes 4.12[PF6]n (n = 0,1,2) includes a crystal structure for the case in which n = 2. This work clearly establishes good electronic and magnetic communication between the iron centers across the bis(ethynyl)naphthalene bridge. All empirical measurements of these naphthyl compounds reveal that their properties fall between those of known phenyl and anthracenyl derivatives. In some cases, the naphthyl derivative behaves as an average of the phenyl and anthracenyl complexes. For example, the comproportionation constant of the naphthyl species falls at the midpoint between those for the phenyl and anthracenyl compounds. The same is true for the UV absorption maxima in all three oxidation states (Fe[II]- Fe[II], MV, and Fe[III]- Fe[III]). The large electronic (2043 cm-1) and magnetic (-526 cm-1) coupling constants were determined via NIR spectroscopy and SQUID magnetometry, respectively. As for the heterotrinuclear species, the iron(II) acetylene, 4.14B[PF6] [{Cp*(dppe)Fe-C C}2-(h 6 – [1,4-napthyl])RuCp*](PF6), [Cp* = h 5 - C5Me5; Fe = FeII] was prepared in high yields with an adapted, regioselective synthesis via the trinuclear vinylidene. Complete characterization, including a crystal structure, of this sandwich complex reveals that the arenophile perturbs the organoiron ligand more in the bis(iron) than in the previously reported mono(iron) case.