Silylene and Disilene Additions to Hexa-2,4-diyne:  Formation of a Propynylsilirene and of Bicyclic Compounds¹

Abstract

Tetra-tert-butyldisilene and di-tert-butylsilylene, generated by photolysis of hexa-tert-butylcyclotrisilane (1), react with the triple bonds of hexa-2,4-diyne to provide the addition products octa-tert-butyl-2-methylene- 5-methyl-3,4,7,8-tetrasilabicyclo[4.2.0]oct-1(6)-ene ( 5) and di-tert-butyl-2-methyl-3-propynylsilirene ( 6). Further treatment of 6 with 1 is thought to proceed via a bis(silirene) derivative to furnish the rearranged tetratert-butyl-3,6-dimethyl-2,5-disilabicyclo[2.2.0]hexa-1(6), 3diene (12). The structures of 5 and 12 were determined by X-ray crystallography.

Silylated Group 14 Ylenes: An Emerging Class of Reactive Compounds

“…One reason why tetrylene complexes of group 4 metallocenes are particularly interesting is that the reactivity of free metallocenes resembles that of free tetrylenes to an astonishing extent. This was shown conclusively by Rosenthal's studies on group 4 metallocenes101 and Weidenbruch's work on silylenes 102–105. In particular, the addition chemistry with unsaturated organic compounds such as alkynes leads to structurally related products (Scheme ) 101.…”

Silylene Reactions with Buta-1,3-diynes: Cycloadditions, Insertions, and Rearrangements

“…Ishikawa et al [11] have previously observed a similar rearrange-for the formation of the bicyclic compound 7, which remained as an open question from a previous publication. [7] ment on heating a dimesitylsilacyclopropene to 250°C, which also furnished the corresponding dialkynylsilane.…”

“…ucts and their structures were confirmed by X-ray crystal-Photolysis of the cyclotrisilane 1 in the presence of the lography. [7] In order to obtain further information relating diyne 9 in a ratio of approximately 1:1 furnished the alkynto the formation of these compounds, especially the bicyclic ylsilirene 10 as a colorless oil in 30% yield; the constitution system 7, we have now examined the reactions of the 1,3of this product was confirmed by a complete NMR analysis. The position of the 29 Si-NMR signal is of particular [ ] typical for silirenes with tert-butyl substituents at the sili- [a] Fachbereich Chemie, Universität Oldenburg, con atom.…”

“…The position of the 29 Si-NMR signal is of particular [ ] typical for silirenes with tert-butyl substituents at the sili- [a] Fachbereich Chemie, Universität Oldenburg, con atom. [7] [8] Carl-von-Ossietzky-Straße 9Ϫ11, D-26111 Oldenburg, Germany…”

Recent Advances in the Chemistry of Silicon–Silicon Multiple Bonds

“…The reaction of 41 with the 1,3-diyne 96 follows an unusual course to afford the bicyclic species 97 isolated in high yield (equation 17) 110 . The reaction sequence may be initiated by the addition of two molecules of 41 to the two triple bonds of 96; this would then be followed by a thermally-allowed 1,5-hydrogen shift together with ring opening and ring closure reactions.…”