Novel Stable Silenes via a Sila-Peterson-type Reaction. Molecular Structure and Reactivity

Reaction of Dichloromethyltris(trimethylsilyl)silane with Organolithium Reagents: Synthesis of an Intramolecularly Donor-Stabilized Silene

“…In contrast, the configuration at the silene-carbon 2 Si C(OSiMe 3 )Ad (1.764 ; Ad 1-adamantyl) [9] and (Me 3 Si) 2 Si Ad' (1.741 ; Ad' 2-adamantylidene) [10] are similar to the value obtained for 7. The SiC distance in 7 is slightly longer than that reported for the uncomplexed stable silene Me 2 SiC(SiMe 3 )(SiMetBu 2 ) (1.702 ),…”

The Direct Synthesis of a Silene–Organometallic Complex

“…Our initial attempts to obtain a silene-platinum complex by a reaction of Pt(PCy 3 ) 2 [8] and the stable silenes 7 [9] and 8 [10] failed, thus leading to a complex mixture of products. Molecular models reveal that the double bond in 7 and 8 is so effectively protected by the very bulky R 1 and R 2 substituents that the desired complex cannot be formed.…”

“…[12] On warming of the reaction mixture (or warming of 9 directly) to À30 8C the transient silene 6 was formed and its formation was monitored by 29 Si NMR (the NMR chemical shifts of 6 are very similar to those of the stable 7 [9] ). [12] The warming of this reaction mixture to room temperature yielded dimer 10, thus supporting the presence of silene 6.…”

The Reaction of Transient 1,1-Bis(trimethylsilyl)silenes with Tris(trimethylsilyl)silyllithium - Synthesis and Structure of Sterically Congested 1-Trimethylsilylalkylpolysilanes

“…In the absence of scavanger reagents they undergo rapid dimerizations [7]. Following the modified Peterson mechanism, recently Apeloig et al succeeded in synthesizing a silene, which is stable at room temperature [8].…”

“…Tris(trimethylsilyl)silyllithium (3) reacted with aldehydes and ketones (molar ratio 2 : 1) according to a modified Peterson mechanism under formation of transient silenes, which were immediately trapped by excess 3 to give the organolithium derivatives (Me 3 Si) 3 SiSi(SiMe 3 ) 2 C(Li)Ŕ 1 R 2 (7). Hydrolysis of 7 afforded the alkylpolysilanes (Me 3 Si) 3 SiSi(SiMe 3 ) 2 CHR 1 R 2 (8). Depending on the substituents R 1 and R 2 , 7 proved to be rather unstable in THF solution and underwent a rapid rearrangement, involving a 1,3-Si,C-trimethylsilyl migration, resulting in the formation of the lithium silanides (Me 3 Si) 2 Si(Li)Si(SiMe 3 ) 2 C(SiMe 3 )R 1 R 2 (9), which were hydrolized during the aqueous workup to give the H-silanes (Me 3 Si) 2 Si(H)Si(SiMe 3 ) 2 C(SiMe 3 )R 1 R 2 (10).…”