ISSN:
1434-1948
Schlagwort(e):
Silicon
;
Silenes
;
1,2-Disilacyclobutanes
;
1,3-Disilacyclobutanes
;
Eliminations
;
Chemistry
;
General Chemistry
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
Notizen:
The regiospecifity of the dimerization of the transient 2-(2-methoxyphenyl)-1,1-bis(trimethylsilyl)silene (6), synthesized by base-initiated trimethylsilanolate elimination from (2-methoxyphenyl)[tris(trimethylsilyl)silyl]methanol (5) according to a modified Peterson mechanism, decisively depends on the donating ability of the solvent in which the silene is generated. In ether, 6 undergoes a formal [2 + 2] dimerization to afford 3,4-bis(2-methoxyphenyl)-1,1,2,2-tetrakis(trimethylsilyl)-1,2-disilacyclobutane (12), whereas in toluene the head-to-tail [2 + 2] cyclodimer, 2,4-bis(2-methoxyphenyl)-1,1,3,3-tetrakis(trimethylsilyl)-1,3-disilacyclobutane (13) was obtained. 1,1-Bis(trimethylsilyl)-2-(2,4,6-trimethoxyphenyl)silene (18), similarly made by a modified Peterson reaction, under the same conditions reacted with the eliminated trimethylsilanolate with readdition at the polar Si=C bond to give, after hydrolysis, 2-(2,4,6-trimethoxybenzyl)-1,1,1,3,3,3-hexamethyl-2-(trimethylsiloxy)trisilane (19). A possible mechanism explaining the solvent-dependent regiospecificity of the dimerization of 6 is discussed. The structures of 12 and 13 were determined on the basis of NMR and MS data as well as X-ray structural analyses.
Zusätzliches Material:
3 Ill.
Materialart:
Digitale Medien
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