142941-19-3Relevant academic research and scientific papers
Silaheterocycles, XVIII. Synthesis and Cycloaddition Reactions of C-Silyl Modified Amino Cyclic Silenes
Auner, Norbert,Penzenstadler, Erika
, p. 805 - 813 (2007/10/02)
The reaction of 2-chloro-1,3-bis(trimethylsilyl)-2-(1'-trimethylsilyl-ethenyl)-1,3-diaza-2-silacyclopentane (5) and LiBut leads to the α-lithio adduct 8 which can be trapped by Me3Si-triflate to give 13b, and is a useful silene precursor.Subsequent 1,2-LiCl elimination yields 2 as an intermediate, which does not cyclodimerise giving a 1,3-disilacyclobutane, but can be trapped by Me3SiOMe and suitable dienes which add across the Si=C bond.In contrast to silene 1, which favours the addition, 2 exclusively forms the Diels-Alder isomers with 2-methyl-1,3-butadiene and 2,3-dimethyl-1,3-butadiene (6 and 7), and the ene products 11 and 12 with norborna-2,5-diene and cyclohexa-1,3-diene, respectively.This quite different cycloaddition behaviour results from the substitution pattern at the Si=C framework, with a changing polarity. 2 thus appears to be a rather electron deficient silene having a polarity more comparable to that of diorganosilenes rather than to 1, which may be compared in its reactivity with Cl2Si=CHCH2But. Key words: Silaheterocycles, Synthesis, 2-Chloro-1,3-bis(trimethylsilyl)-2-(1'-trimethylsilyl-ethenyl)-1,3-diaza-2-silacyclopentane, Formation of Silenes, Cycloaddition Reactions
