A one-pot, two step synthesis of 2,2-disubstituted 1-nitroalkenes

The reactions of ketones 1a-o, nitromethane 2, and a stoichiometric amount of piperidine 3a or ethylenediamine 3b in the presence of mercaptan 6a in THF or CH₃CN solution give high yields of β-nitrosulfides 7a-o. The latter can be oxidized by 8a (m-CPBA or m-CPBA/AcOH) at 0°C, 8b (H₂O₂/AcOH), or 8c (H₂O₂) at room temperature, thus generating β-nitroalkylsulfoxides 9a-o, which then undergo elimination to produce medium to high yields of 2,2-disubstituted-1-nitroalkenes 5a-o, when refluxed in a solution of ClCH₂CH₂Cl (1,2-dichloroethane). After preparation from 1a-o, 2, 3, and 6a, 7a-o were oxidized with 8a, 8b, or 8c in a mixture of CH₃CN and ClCH₂CH₂Cl to generate β-nitrosulfoxides 9a-o, which then underwent elimination under refluxing under one-pot conditions. Compounds 14 and 15g were also prepared using 13, 2, 3b, and 6, in a similar manner.     

Half-sandwich η-arene–ruthenium(II) complexes bearing 1-alkyl(benzyl)-imidazo[4,5-f][1,10]-phenanthroline (IP) derivatives: the effect of alkyl chain length of ligands to catalytic activity

The reaction of bromoalkanes (R–Br; (3), R=C_nH_2n+1, n=4 (a), 8 (b), 12 (c),18 (d)) and bromobenzyl derivatives (R′–Br; (4), R′=CH₂C₆H₂(CH₃)₃-2,4,6 (a); CH₂C₆H(CH₃)₄-2,3,5,6 (b); CH₂C₆(CH₃)₅ (c)) with 1H-imidazo[4,5-f][1,10]-phenanthroline (IP)(L₂) gave the corresponding 1-R-imidazo[4,5-f][1,10]-phenanthroline (IPR)(L_3a–d) and 1-R′-imidazo[4,5-f][1,10]-phenanthroline(IPR')(L_4a–c) ligands, respectively. Treatment of L_3a–d and L_4a–d with [Ru(p-cymene)Cl₂]₂ led to the formation of [Ru(p-cymene)(IPR)Cl]Cl (RuL_3a–d) and [Ru(p-cymene)(IPR′)Cl]Cl (RuL_4a–c). New ruthenium(II) complexes RuL_3a–d and RuL_4a–c were characterized by elemental analysis, FTIR, UV–visible and NMR spectroscopy. In order to understand effects of these changes on the N-substituent of imidazol on IP and how they translate to catalytic activity, these new RuL₂, RuL_3a–d and RuL_4a–c were applied in the transfer hydrogenation of ketones by 2-propanol in presence of potassium hydroxide. The activities of the catalysts were monitored by NMR and GC analysis.     

Syntheses of a stable tristibine and of related antimony compounds with the 2,6-dimesitylphenyl (Dmp) substituent

DmpSbBr₂ (Dmp = 2,6-Mes₂C₆H₃) (1) is obtained by the reaction of DmpMgBr with SbCl₃. The reaction of 1 with KI in ethanol gives DmpSbI₂ (2). Dmp(Ph)SbBr (3) is prepared from DmpMgBr and PhSbCl₂. Compound 1 or 3 react with LiAlH₄ to form DmpSbH₂ (4) or Dmp(Ph)SbH (5). Compound 4 reacts with MeI in presence of DBU to give Dmp(Me)SbH (6). DmpSb(SbMe₂)₂ (7) is obtained from 4 and Me₄Sb₂. Elimination of hydrogen from 6 gives [Dmp(Me)Sb]₂ (8). Hydrolysis of 3 gives Dmp(Ph)SbOH (9). The molecular structures of 1-3, 5, 8 and 9 were determined by X-ray diffraction on single crystals.     

Light-harvesting composites of directly connected porphyrin-phthalocyanine dyads and their coordination dimers

Directly linked porphyrin (Por)-phthalocyanine (Pc) heterodyads (H₂Por-H₂Pc and H₂Por-ZnPc) with an imidazolyl group at porphyrin’s meso-position were synthesized. Introduction of a zinc ion into the porphyrin afforded stable complementary dimers of the heterodyads. The heterodyads and their dimers gave extensive and strong absorption bands owing to the porphyrin and phthalocyanine components and induced an efficient energy transfer from porphyrin to phthalocyanine. Strong fluorescence from phthalocyanine was observed in the case of H₂Por-H₂Pc.     

Palladium complexes of N-aryl-2-pyridylamines

Palladium complexes of N-phenyl-2-pyridylamine (4) and dipyridylamine substrates (7, 11) have been studied. Due to the coordination ability of the pyridine-nitrogen atoms, the pyridyl substrates, 4, 7, 11 were subjected to Pd(OAc)₂ complexations and a number of N-aryl-2-pyridylamine Pd complexes (13-17) were isolated and characterised, in particular by NMR and ESI-MS. A new method for the preparation of the acetato-bridged six-membered ring palladacycle complex (13) of 4 is reported. The dipyridyl amines 7, 11 formed cis/trans bis-dentate acetato-bridged dimeric Pd₂Lig₂(OAc)₂ (14a,b/16a,b) and Pd₃Lig₂(OAc)₄ complexes (15a,b/17a,b). The N-aryl-2-pyridylamine substrates (4, 7, 11) were prepared by oxidative nucleophilic substitution, by 1,3-cycloaddition reaction or by Buchwald amination.     

Synthesis and reactivity of new functionalized Pd(II) cyclometallated complexes with boronic esters

Treatment of the functionalized Schiff base ligands with boronic esters 1a, 1b, 1c and 1d with palladium (II) acetate in toluene gave the polynuclear cyclometallated complexes 2a, 2b, 2c and 2d, respectively, as air-stable solids, with the ligand as a terdentate [C,N,O] moiety after deprotonation of the -OH group. Reaction of 1j with palladium (II) acetate in toluene gave the dinuclear cyclometallated complex 5j. Reaction of the cyclometallated complexes with triphenylphosphine gave the mononuclear species 3a, 3b, 3c, 3d and 6j with cleavage of the polynuclear structure. Treatment of 2c with the diphosphine Ph₂PC₅H₄FeC₅H₄PPh₂ (dppf) in 1:2 molar ratio gave the dinuclear cyclometallated complex 4c as an air-stable solid.Deprotection of the boronic ester can be easily achieved; thus, by stirring the cyclometallated complex 3a in a mixture of acetone/water, 3e is obtained in good yield. Reaction of the tetrameric complex 2a with cis-1,2-cyclopentanediol in chloroform gave complex 2c after a transesterification reaction. Under similar conditions complexes 3a and 3d behaved similarly: with cis-1,2-cyclopentanediol, pinacol or diethanolamine complexes 3c, 3b, 3g and 3f, were obtained. The pinacol derivatives 3b and 3g experiment the Petasis reaction with glyoxylic acid and morpholine in dichloromethane to give complexes 3h, and 3i, respectively.     

Dibromomethane as one-carbon source in organic synthesis: a versatile methodology to prepare the cyclic and acyclic α-methylene or α-keto acid derivatives from the corresponding terminal alkenes

Ozonolysis of mono-substituted alkenes A-1 followed by reacting with a preheated mixture of CH₂Br₂-Et₂NH affords α-substituted acroleins A-2 in good yields. Under very mild reaction conditions, these α-substituted acroleins A-2 can be easily converted to α-methylene esters A-4, which could be further converted to the corresponding α-keto esters A-5. This methodology can be also applied to the preparation of α-methylene lactones B-4, α-methylene lactams, and α-keto lactones B-5 with various ring sizes.     

α-Telluration of 2,4,6-trimethylacetophenone under mild conditions: Role of steric factor in the solid state structures of Te(II and IV) compounds

Elemental tellurium inserts into the C_sp3-Br bond of α-bromomesitylmethyl ketone and due to its strong carbophilic character affords the crystalline C-tellurated derivative of 2,4,6-trimethylacetophenone, (MesCOCH₂)₂TeBr₂, 1b in over 80% yield. Electrophilic substitution of the parent ketone with aryltellurium trichlorides, at room temperature, gives nearly quantitative yields of unsymmetrical alkylaryltellurium dichlorides (MesCOCH₂)ArTeCl₂ (Ar = mesityl, Mes, 2a; 1-naphthyl, Np, 3a; anisyl, Ans, 4a). Fairly stable mesitoylmethyltellurium(II) derivatives, (MesCOCH₂)₂Te, 1 and (MesCOCH₂)ArTe (Ar = Mes, 2; Np, 3 and Ans, 4) obtained as the reduction products of their dihalotellurium(IV) analogues, readily undergo oxidative addition of dihalogens to afford the corresponding (MesCOCH₂)₂TeX₂ (X = Cl, 1a; Br 1b; I, 1c) and (MesCOCH₂)ArTeX₂ (X = Cl, Br, I, Ar = Mes, 2a, 2b, 2c; Np, 3a, 3b, 3c and Ans, 4a, 4b, 4c). Crystallographic structural characterization of 1, 1b, 2, 2a, 2b, 2c, 3, 3a and 4c illustrates that the steric demand of mesityl group appreciably influences primary geometry around the 5-coordinate Te(IV) atom when it is bound directly to it. It also makes the Te atom inaccessible for the ubiquitous Te?X intermolecular secondary bonding interactions that result in supramolecular structures. In the crystal lattice of symmetrical telluroether 1, an interesting supramolecular synthon based upon reciprocatory weak C-H?O H-bonding interaction gives rise to chains via self-assembly.     

Metal-organic coordination architectures of azole heterocycle ligands bearing acetic acid groups: Synthesis, structure and magnetic properties

Four new coordination complexes with azole heterocycle ligands bearing acetic acid groups, [Co(L¹)₂]_n (1), [CuL¹N₃]_n (2), [Cu(L²)₂·0.5C₂H₅OH·H₂O]_n (3) and [Co(L²)₂]_n (4) (here, HL¹=1H-imidazole-1-yl-acetic acid, HL²=1H-benzimidazole-1-yl-acetic acid) have been synthesized and structurally characterized. Single-crystal structure analysis shows that 3 and 4 are 2D complexes with 4⁴-sql topologies, while another 2D complex 1 has a (4³)₂(4⁶)-kgd topology. And 2 is a 3D complex composed dinuclear μ_1,1-bridging azido Cu^II entities with distorted rutile topology. The magnetic properties of 1 and 2 have been studied.     

Synthesis, photophysical properties, and cyanide detection in aqueous solution of BF2-curcumin dyes

Derivatives of difluoroboron curcumin (BF₂-curcumin, BF₂-cur(OMe)₂, BF₂-cur(OTs)₂, and BF₂-curOTs), were synthesized. All compounds possessed electron donor moieties at both ends of the conjugated π system and an electron acceptor moiety in the middle of the molecules (D-A-D system) and should exhibit different optical properties depending on substituents on the benzene rings. Photophysical properties of curcumin and difluoroboron curcumin derivatives were explored. The electron-withdrawing substituent could decrease the electron acceptability of BF₂-acceptor moiety resulting in the hypsochromic shift of both absorption and emission bands. BF₂-curcumin and BF₂-cur(OMe)₂ displayed the positive solvatochromic effect relying predominantly on polarity and polarizability of the solvent. Interestingly, BF₂-curcumin showed high selectivity and sensitivity towards cyanide with the detection limits of 22 μM and 0.14 μM measured by visual detection and UV-vis spectrophotometry, respectively. Compared to the original curcumin, BF₂-curcumin offered a remarkably promising detection of cyanide with 66-fold enhancement in aqueous media (4:1 of CH₃CN/H₂O).     

Addition of 2-tert-butyldimethylsilyloxythiophene to activated quinones: an approach to thia analogues of kalafungin

The uncatalyzed reaction of 2-tert-butyldimethylsilyloxythiophene 2 with 1,4-quinones bearing either an electron withdrawing acetyl or a carbomethoxy group at C-2, was investigated. No reaction was observed using 1,4-quinones 8 and 9 bearing an ester group at C-2 whereas use of 1,4-quinones 10 and 11 bearing an acetyl group at C-2 only provided low yields of the silyloxythiophenes 15 and 16 resulting from electrophilic substitution of the silyloxythiophene by the 1,4-quinone. Use of the Lewis acids InCl₃, Cu(OTf)₂ and BF₃·Et₂O were investigated in an effort to improve the yield of the desired annulation reaction. BF₃·Et₂O proved to be the optimum catalyst for the synthesis of thiolactone naphthofuran adducts 14 and 18 from 1,4-naphthoquinones 9 and 11, respectively. Reaction of 2-tert-butyldimethylsilyloxythiophene 2 with 1,4-benzoquinones 8 and 10 bearing a carbomethoxy or an acetyl group at C-2, respectively, afforded thiolactone benzofuran adducts 13 and 17, respectively, catalyzed by either InCl₃ or Cu(OTf)₂. Addition of 2-tert-butyldimethylsilyloxythiophene 2 to 3-acetyl-5-methoxy-1,4-naphthoquinone 12 afforded adduct 19 that underwent oxidative rearrangement to thiolactone pyranonaphthoquinone 20 using ceric ammonium nitrate in acetonitrile, thus providing a novel approach for the synthesis of a thia analogue of the pyranonaphthoquinone antibiotic kalafungin.     

Synthesis of functionalized bicyclo[3.2.1]octan-6-ones for diterpenoids: allylsilane directed Pummerer reaction: insertion reactions of diazoketones

The sulfide 5 underwent Pummerer cyclization to give 6, whereas the allyl silane analog 10 produced the bicyclo[3.2.1]octanones 11 and 11a. Extension of this methodology to 15 resulted in 16 without the necessity for allyl silane activation. The intermediate diazoketone 14 on treatment with BF₃·OEt₂ gave 17, 18 and 19, whereas the saturated adduct 22 on treatment with Rh₂(OAc)₄ gave 23.     

A facile approach for the synthesis of novel substituted 4H-chromenes and condensation reactions of 4H-chromenes leading to chromenopyrrolones and triazolylchromenopyrrolones

A facile method has been developed for the synthesis of 4H-chromene-3-carboxylates 3a–d by the nucleophilic substitution reaction of 2-hydroxy-2H-chromene-3-carboxylates 2a–d with triethylsilane in the presence of BF₃·O(C₂H₅)₂. Cyclocondensation of 4H-chromene-3-carboxylates 3a–d with benzylamines 4a–d afforded a series of 2,3-dihydrochromenopyrrolones 5a–p and with propargylamine afforded 2-propynyl-2,3-dihydrochromenopyrrolones 6a–d. Click reaction of 6a–d with benzyl azides 7a–d provided a series of 1H-1,2,3-triazolylmethyl-2,3-dihydrochromenopyrrolones 8a–p. Thus synthesized compounds 3a–d, 5a–p, 6a–d, and 8a–p are novel heterocyclic compounds and being reported for the first time.     

Effect of π-accepting substituent on the reactivity and spectroscopic characteristics of triarylbismuthanes and triarylbismuth dihalides

Competitive chlorination of p-substituted triarylbismuthanes 1 [(p-XC₆H₄)₃Bi; a: X = OMe, c: Cl, d: CO₂Et, e: CF₃, f: CN, g: NO₂] and trimesitylbismuthane (2,4,6-Me₃C₆H₂)₃Bi 1h by sulfuryl chloride was carried out against 1b (X = H) and the effect of these substituents on the formation of triarylbismuth dichlorides 2 was studied. The relative ratios 2/2b decreased with increasing electron-withdrawing ability of the substituents (2a/2b = 53/47, 2c/2b = 33/67, 2d/2b = 35/65, 2e/2b = 29/71, 2f/2b = 16/84, 2g/2b = 0/100, 2h/2b = 46/54), indicating a lowering of reactivity of the lone pair on the bismuth atom. Pd-Catalyzed degradation of 2a-g and their difluorides 3 giving biaryls 4 was promoted by the electron-withdrawing p-substituents in the equatorial aryl groups but suppressed by the more electronegative fluorine atoms in the apical positions. This is in fairly good accord with the stability of the trigonal bipyramidal geometry. The ¹³C NMR study of 1-3 showed that the signals due to the ipso carbons (C1) attached to the bismuth atom shift downfield with increasing electron-withdrawing nature of the p-substituents. No such tendency was observed in other aromatic ring carbons. The electronic effect on the C1 atoms, similar to that on the chlorination of 1 and degradation of 2 and 3, indicates the significant participation of the C1 atoms in these reactions through the Bi-C1 bonds.     

Dimolybdenum complexes containing anions of N,N′-bis(pyrimidine-2-yl)formamidine and N-(2-pyrimidinyl)formamide

The reactions of Mo₂(O₂CCH₃)₄ with different equivalents of N,N′-bis(pyrimidine-2-yl)formamidine (HL1) and N-(2-pyrimidinyl)formamide (HL2) afforded dimolybdenum complexes of the types Mo₂(O₂CCH₃)(L1)₂(L2) (1) trans-Mo₂(L1)₂(L2)₂ (2) cis-Mo₂(L1)₂(L2)₂ (3) and Mo₂(L2)₄ (4). Their UV–Vis and NMR spectra have been recorded and their structures determined by X-ray crystallography. Complexes 2 and 3 establish the first pair of trans and cis forms of dimolybdenum complexes containing formamidinate ligands. The L1 ligands in 1–3 are bridged to the metal centers through two central amine nitrogen atoms, while the L2 ligands in 1–4 are bridged to the metal centers via one pyrimidyl nitrogen atom and the amine nitrogen atom. The Mo–Mo distances of complexes 1 [2.0951(17) Å], 2 [2.103(1) Å] and 3 [2.1017(3) Å], which contain both Mo?N and Mo?O axial interactions, are slightly longer than those of complex 4 [2.0826(12)–2.0866(10) Å] which has only Mo?O interactions.     

Exploring the reactivity of an N-pyrazole, P-phosphine hybrid ligand with Cu(I), Ag(I) and Au(I) precursors

The reactivity of (3,5-dimethyl-1H-pyrazol-1-yl)ethyldiphenylphosphine (L) hybrid ligand against Cu(I), Ag(I) and Au(I) has been assayed and compounds [Cu(L)₂](PF₆) (1), [Ag(L)]₂(PF₆)₂·2C₂H₄Cl₂·2C₄H₁₀O (2) and [AuCl(L)]₂ (3) have been isolated and fully characterised. A fully characterisation by analytical and spectroscopic methods of 1-3 are presented and X-ray crystal structures of 1 and 2 are also reported. The similar data obtained between 2 and 3 permits to do a serious purpose of the structure of 3 in solid and solution.     

Triphenyl lead, tin and germanium coordination compounds derived from 9H-3-thia-1,4a,9-triaza-fluorene-2,4-dithione

Reactions of potassium 4-thioxo-3-thia-1,4a,9-triaza-fluorene-2-thiolate with Ph₃PbCl, Ph₃SnCl and Ph₃GeCl provided the corresponding metal pentacoordinated compounds 2-4. Addition of THF afforded their hexacoordinated derivatives (5-7). Adducts of 2 and 3 with DMSO (8, 10), pyridine (9, 11), Ph₃PO (12, 14) CH₃OH (13, 15), respectively were synthesized. Compound 2 afforded the H₂O adduct (16). In all cases the metal atom is chelated by the ligand through a covalent bond with S2 and a coordination bond with N1 forming four membered rings. Compounds were identified by ¹H, ¹³C, ¹⁵N, ¹¹⁹Sn and ²⁰⁷Pb. X-ray diffraction structures of 2, 3, 8, 9, 11, 14 and 16 were obtained.     

Structural diversity in the self-assembly of Ag(I) complexes containing 2-amino-5-halopyrimidine

A series of Ag(I) complexes containing the 2-amino-5-halopyrimidine ligands have been synthesized and their structures characterized by X-ray crystallography. The isomorphous complexes Ag(L-Cl)₂(CF₃SO₃) (L-Cl = 2-amino-5-chloropyrimidine), 1, and Ag(L-Br)₂(CF₃SO₃) (L-Br = 2-amino-5-bromopyrimidine), 2, are mononuclear, while [Ag(L-Br)(CF₃SO₃)]₆·6C₄H₁₀O, 3, and [Ag(L-I)(CF₃SO₃)]₆ (L-I = 2-amino-5-iodopyrimidine), 4, show cyclic self-assembly of six Ag(Ι) atoms and six L-X ligands, resulting in 24-membered metallocycles. The complex [Ag(L-I)(CF₃SO₃)]_∞, 5, forms 1D zigzag chains which are linked through C-I?Ag and Ag?O interactions to form a 3D structure. The tetranuclear complexes [Ag(L-X)(NO₃)]₄ [X = Cl, 6; Br, 7] form 16-membered metallocycles, while [Ag(L-X)(ClO₄)]_∞ [X = Cl, 8; Br, 9] exhibit helical chains. The different structure of 5 from 1 and 2 appears to be due to the stronger nucleophilic character of the iodine atom. In these complexes, the relatively smaller NO₃⁻ anions lead to the formation of tetranuclear metallocycles and the larger CF₃SO₃⁻ anions support the hexanuclear metallocycles, whereas the ClO₄⁻ anions induce the helical chains.     

Osmium assisted C-H activation and CN cleavage of N-(2′-hydroxyphenyl) benzaldimines. Synthesis, structure and electrochemical properties of some organoosmium complexes

Reaction of N-(2′-hydroxyphenyl)-4-R-benzaldimines (L-R, R = OCH₃, CH₃, H, Cl and NO₂) with [Os(PPh₃)₃Br₂] in refluxing 2-methoxyethanol in the presence of triethylamine affords two families of organoosmium complexes (1-R and 2-R). In both 1-R and 2-R complexes a benzaldimine ligand is coordinated to the metal center as tridentate C,N,O-donor. In the 1-R complexes, a bidentate N,O-donor imionsemiquinonate ligand, derived from the hydrolysis of another benzaldimine, and a PPh₃ ligand are also coordinated to osmium. In the 2-R complexes, a carbonyl, derived from decarbonylation of 4-R-benzaldehyde (derived from the same hydrolysis stated above), and two PPh₃ ligands take up the remaining coordination sites on osmium. Structures of the 1-Cl and 2-OCH₃ complexes have been determined by X-ray crystallography. All the 1-R and 2-R complexes are diamagnetic, and show characteristic ¹H NMR signals and intense MLCT transitions in the visible region. Cyclic voltammetry on the 1-R complexes shows a reversible Os(III)-Os(IV) oxidation within 0.47-0.67 V (vs SCE), followed by an irreversible oxidation of the imionsemiquinonate ligand within 1.10-1.36 V. An irreversible Os(III)-Os(II) reduction is also displayed by the 1-R complexes within −1.02 to −1.14 V. Cyclic voltammetry on the 2-R complexes shows a reversible Os(II)-Os(III) oxidation within 0.29-0.51 V, followed by a quasi-reversible oxidation within 1.04-1.29 V, and an irreversible reduction of the coordinated benzaldimine ligand within −1.16 to −1.31 V.     

Intramolecular rearrangement of organosilyl groups between oxygen and nitrogen in aminosiloxanes - a joint experimental-theoretical study, part II

Lithium amino-di-tert-butylsilanolate reacts with halosilanes to give 1-silylamino-1,3-siloxanes (1-7). The tetrakis(1-silylamino)siloxane thermally condenses yielding a spirocyclic six-membered ring (8). One six-membered ring of 8 forms a boat and the other has a twist conformation. Lithium salts of amino-disiloxanes form silylamino-silanolates or amido-disiloxanes. The first includes a 1,3-silyl group migration from the oxygen to the nitrogen atom. The energies of the isomeric lithium salts of model compounds are calculated and show that the lithium-trimethylsilylamino-dimethylsilanolate III is 0.7 kcal/mol more stable than the isomeric lithium-1,3-disiloxaneamide V. Experiments show that the lithium salts of amino-1,3-disiloxanes, (Me₃C)₂SiNH₂-O-R (R = SiMe₃, SiMe₂Ph, SiF₂CMe₃) reacts with ClSiMe₃, FSiMe₂Ph or F₃SiCMe₃ under a 1,3-O-N-silyl group migration to give the 1-silylamino-1,3-disiloxanes 9-11. If the trimethylsilyl group is substituted by SiMeF₂, the difference between the isomers III′ and V′ is even smaller, 0.12 kcal/mol, and the barrier to reaction via the dyotropic transition state is calculated to be 10.1 kcal/mol. Interestingly, the fluorine atoms allow for two other isomers VI and VIII which are even lower in energy. The low difference in the energies of III and V respectively VI and VIII explains that in absence of steric and/or electronic restraints the lithium salts of amino-1,3-disiloxanes react halosilanes to give both isomeric silylamino-1,3-disiloxanes, e. g. the lithiated (Me₃C)₂SiNH₂-O-SiF₂CMe₃ reacts with F₂SiMe₂ or F₃SiPh to give the structural isomers 12, 13, and 14, 15.The silyl group migration can be prevented kinetically, e. g. the lithium salts of (Me₃C)₂SiNH₂-O-R (R = SiF(N(CHMe₂)₂)₂, SiH(CMe₃)₂) react with F₂SiMe₂ or F₂Si(CMe₃)₂ to 16 and 17. A thermodynamically prevented rearrangement is observed in the reaction of lithiated (Me₃C)₂SiNH₂-O-SiMe₃ with F₃SiR (R = CMe₃ (18), Ph (19), N(SiMe₃)₂ (20), C₆H₂ (CMe₃)₃ (21). 18-21 ((Me₃C)₂SiNHSiF₂R)-O-SiMe₃) are formed.LiF-elimination from (Me₃C)₂SiNHLiO-SiF₂Me leads to the formation of the eight-membered (SiOSiN)-ring 22. The most stable lithium salts of 1-silylamino-1,3-disiloxanes form amides. This explains that in further reactions with halosilanes, the new ligand is bonded with the nitrogen atom (28-30). In results of crystal structure determinations new lithium-1-fluorosilylamino-1,3-disiloxanes of 20, (21, 23-25) are presented. 23 crystallizes as tricyclic, 24 as an unknown pentacyclic, and 25, as monomeric compound. In 25 the shortest Si-N bond length (157.9 pm) with four coordinate silicon is found. Lithium salts of 1-fluorosilylamido-1,3-disiloxanes lose thermally LiF with formation of siloxane substituted cyclodisilazanes, 26 and 27. Crystal structures of 4, 8, 17, 20, 21, 22, 23, 24, 25, 26, 28 are presented.