ISSN:
1434-1948
Schlagwort(e):
Silanes
;
Rearrangements
;
Polysilanes
;
Hypersilylalcohols
;
1,2-Trimethylsilyl migration
;
Chemistry
;
General Chemistry
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
Notizen:
In the presence of strong acids, such as HCl or H2SO4, 1-hydroxyalkyltris(trimethylsilyl)silanes (Me3Si)3Si-C(OH)R1R2 (1a-f) isomerize by 1,2-Me3Si/OH exchange to give the trimethylsilylmethylsilanols (Me3Si)2Si(OH)-C(SiMe3)R1R2 (4a-f) [R1,R2: a: Me, Me; b: H, 4-MeC6H4; c: H, 4-iPrC6H4; d: H, Mes; e: H, 2-Me2NC6H4; f: H, 2,4,6-(MeO)3C6H2]. A mechanism for the isomerization is proposed. In the case of the reaction of 1d with sulfuric acid, the silylsulfate (Me3Si)2Si(OSO3H)-C(SiMe3)HMes (5) was isolated. 5 is the intermediate in the H2SO4-catalyzed isomerization of 1d and was converted in situ with methanol, acetic anhydride, HF or HCl to give the respective methoxysilane 6, acetoxysilane 7, fluorosilane 8, or chlorosilane 9. Deprotonation of 4a, d, f with sodium hydride causes a further rearrangement, a 1,3-C,O-trimethylsilyl migration, to give the siloxanes (Me3Si)2(Me3SiO)Si-CHR1R2 (11a, d, f).
Materialart:
Digitale Medien
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