Synthesis of (SiNSiO) four-membered rings; crystal structure of (Me3C)2SiMe3

Schmidt‐Baese, D.; Klingebiel, Uwe

doi:10.1016/0022-328x(89)87140-2

Cited by 25 publications

(6 citation statements)

References 10 publications

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“…This means that in the lithiation reaction the silyl substituent on the oxygen atom is displaced by the Lewis acidic lithium, so that an O Ǟ N silyl group migration is observed. [8] This rearrangement can be prevented by bulky groups [Equation (2)]. Siloxaneamides of type II are then formed.…”

Section: Introductionmentioning

confidence: 99%

“…Therefore the success of the substitution of the silyl groups determines which isomer is obtained. [8] In with formation of a dimeric lithium derivative through the Li−N bond (4). In 4 the transannular Si···Si distance was found to be 237.2 pm, which is the shortest distance so far found between two silicon atoms contained in four-membered rings.…”

Section: Introductionmentioning

confidence: 99%

“…[11] However, they are direct precursors of four-membered (SiϪOϪSiϪN) rings when catalytic amounts (1Ϫ5%) of fluorosilanes are added to a solution of the lithium compounds. [8,12] In this paper we describe the preparation of 1-[amino-1,1-di(tert-butyl)]-3-[2,4,6-tri(tert-butyl)phenyl]-3,3-difluoro-1,3-disiloxane, its cyclisation to the first (SiϪNHϪSiϪO) four-membered ring system, and the formation of its lithium derivative.…”

Section: Introductionmentioning

confidence: 99%

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1-Oxa-3-aza-2,4-disilacyclobutanes − Synthesis, X-ray Structures, and Reactivity

Klingebiel

Noltemeyer

2001

Eur. J. Inorg. Chem.

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Lithium aminodi(tert‐butyl)silanolate reacts with F3SiR to give the aminosiloxane (Me3C)2SiNH2−O−SiF2R [1; R = 2,4,6‐(tBu)3C6H2]. In the reaction of 1 with BuLi a four‐membered (Si−O−Si−NH) ring system 2 is formed [−(Me3C)2Si− O−SiFR−NH−]. The amino‐1,3‐disiloxane RSiF2−NH−Si(CMe3)2−O−SiF2R (3) is obtained from dilithiated amino(di‐tert‐butyl)silanol and F3SiR. Compound 1 reacts with BuLi with formation of a dimeric lithium derivative through the Li−N bond (4). In 4 the transannular Si···Si distance was found to be 237.2 pm, which is the shortest distance so far found between two silicon atoms contained in four‐membered rings. Compound 4 reacts with Me3SiOSO2CF3 with substitution of the lithium by the Me3Si group to give 5.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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1-Oxa-3-aza-2,4-disilacyclobutanes − Synthesis, X-ray Structures, and Reactivity

Klingebiel

Noltemeyer

2001

Eur. J. Inorg. Chem.

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“…Die Si±O±Si-Winkel sind erwartungsgema Èû etwas gro È ûer als der Si±N±Si-Winkel. Derartige Winkelaufweitungen wurden auch bei vier-und achtgliedrigen (NSiOSi)-Ringen gefunden [10,11]. Die Summe der Bindungswinkel von N(1) betra È gt 359,5°, N(1) ist also planar umgeben.…”

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Bis(fluor-diisopropylsilyl)amin als Baustein anorganischer Heterocyclen

Marcus

Klingebiel

Lameyer³

1998

Z. anorg. allg. Chem.

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“…(Me 3 C) 2-Si(OH)NH 2 [1][2][3][4][5][6][7][8][9][10][11][12]. The lithium salt of this species was characterized as a tetramer, forming a Li-O cubane [1], while the sodium and potassium salts crystallize as hexagonal prisms [4].…”

Section: Introductionmentioning

confidence: 99%

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

Kliem

Klingebiel

Noltemeyer

et al. 2005

Journal of Organometallic Chemistry

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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, (Me 3 C) 2 SiNH 2 -O-R (R = SiMe 3 , SiMe 2 Ph, SiF 2 CMe 3 ) reacts with ClSiMe 3 , FSiMe 2 Ph or F 3 SiCMe 3 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 SiMeF 2 , the difference between the isomers III 0 and V 0 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 (Me 3 C) 2 SiNH 2 -OSiF 2 CMe 3 reacts with F 2 SiMe 2 or F 3 SiPh to give the structural isomers 12, 13, and 14, 15.The silyl group migration can be prevented kinetically, e. g. the lithium salts of (Me 3 C) 2 SiNH 2 -O-R (R = SiF(N(CHMe 2 ) 2 ) 2 , SiH(CMe 3 ) 2 ) react with F 2 SiMe 2 or F 2 Si(CMe 3 ) 2 to 16 and 17. A thermodynamically prevented rearrangement is observed in the reaction of lithiated (Me 3 C) 2 SiNH 2 -O-SiMe 3 with F 3 SiR (R = CMe 3 (18), Ph (19), N(SiMe 3 ) 2 (20), C 6 H 2 (CMe 3 ) 3 (21). 18-21 ((Me 3 C) 2 SiNHSiF 2 R)-O-SiMe 3 ) are formed.LiF-elimination from (Me 3 C) 2 SiNHLiO-SiF 2 Me 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.

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Synthesis of (SiNSiO) four-membered rings; crystal structure of (Me3C)2SiMe3

Cited by 25 publications

References 10 publications

1-Oxa-3-aza-2,4-disilacyclobutanes − Synthesis, X-ray Structures, and Reactivity

1-Oxa-3-aza-2,4-disilacyclobutanes − Synthesis, X-ray Structures, and Reactivity

Bis(fluor-diisopropylsilyl)amin als Baustein anorganischer Heterocyclen

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

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