2,2‐Difluor‐1,3‐diaza‐2‐sila‐cyclopenten – Synthese und Reaktionen

2,2‐Difluor‐1,3‐diaza‐2‐sila‐cyclopentene – Synthesis and Reactions N,N′‐Di‐ tert ‐butyl‐1,4‐diaza‐1,3‐butadiene reacts with elemental lithium under reduction to give a dilithium salt, which forms with fluorosilanes the diazasilacyclopentenes 1 – 4 ; (HCNCMe 3 ) 2 SiFR, R = F ( 1 ), Me ( 2 ), Me 3 C ( 3 ), N(CMe 3 )SiMe 3 ( 4 ). As by‐product in the synthesis of 1 , the tert ‐butyl‐amino‐methylene‐ tert ‐butyliminomethine substituted compound 5 was isolated, R = N(CMe 3 )‐CH 2 ‐CH = NCMe 3 . 5 is formed in the reaction of 1 with the monolithium salt of the 1,4‐diaza‐1,3‐butadiene in an enamine‐imine‐tautomerism. 1 reacts with lithium amides to give (HCNCMe 3 ) 2 SiFNHR, 6 – 12 , R = H ( 6 ), Me ( 7 ), Me 2 CH ( 8 ), Me 3 C ( 9 ), H 5 C 6 ( 10 ), 2,6‐Me 2 C 6 H 3 ( 11 ), 2,6‐(Me 2 CH) 2 C 6 H 3 ( 12 ). The reaction of 12 with LiNH‐2.6‐(Me 2 CH) 2 C 6 H 3 leads to the formation of (HCNCMe 3 ) 2 Si(NHR) 2 , ( 13 ). In the presence of n ‐BuLi, 12 forms a lithium salt which looses LiF in boiling toluene. Lithiated 12 adds this LiF and generates a spirocyclic tetramer with a central eight‐membered LiF‐ring ( 14 ), [(HCNCMe 3 ) 2 Si(FLiFLiNR)] 4 , R = 2,6‐(Me 2 CH) 2 C 6 H 3 . ClSiMe 3 reacts with lithiated 12 to yield the substitution product (HCNCMe 3 ) 2 SiFN(SiMe 3 ) R, ( 15 ). The crystal structures of 1 , 5 , 6 , 9 , 11 , 13 , 14 are reported.