Head-to-Head versus Head-to-Tail Dimerizations of Transient Silenes – The Solvent-Dependent Regiospecifity of the Dimerization of 2-(2-Methoxyphenyl)-1,1-bis(trimethylsilyl)silene
✍ Scribed by Kathleen Schmohl; Matthias Blach; Helmut Reinke; Rhett Kempe; Hartmut Oehme
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 363 KB
- Volume
- 1998
- Category
- Article
- ISSN
- 1434-1948
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✦ Synopsis
The regiospecifity of the dimerization of the transient 2-(2-cyclobutane (13) was obtained. 1,1-Bis(trimethylsilyl)-2-(2,4,6-trimethoxyphenyl)silene (18), similarly made by a methoxyphenyl)-1,1-bis(trimethylsilyl)silene (6), synthesized by base-initiated trimethylsilanolate elimination from (2-modified Peterson reaction, under the same conditions reacted with the eliminated trimethylsilanolate with methoxyphenyl)[tris(trimethylsilyl)silyl]methanol (5) according to a modified Peterson mechanism, decisively readdition at the polar Si=C bond to give, after hydrolysis,2-(2,4,6-trimethoxybenzyl)-1,1,1,3,3,3-hexamethyl-2-(trimeth-depends on the donating ability of the solvent in which the silene is generated. In ether, 6 undergoes a formal [2 + 2] ylsiloxy)trisilane ( ). A possible mechanism explaining the solvent-dependent regiospecificity of the dimerization of 6 is dimerization to afford 3,4-bis(2-methoxyphenyl)-1,1,2,2tetrakis(trimethylsilyl)-1,2-disilacyclobutane (12), whereas in discussed. The structures of 12 and 13 were determined on the basis of NMR and MS data as well as X-ray structural toluene the head-to-tail [2 + 2] cyclodimer, 2,4-bis-(2methoxyphenyl)-1,1,3,3-tetrakis(trimethylsilyl)-1,3-disila-analyses.