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.