Stereoisomerization of Cyclic Silanols.
Chem Asian J
; 12(11): 1224-1233, 2017 Jun 01.
Article
en En
| MEDLINE
| ID: mdl-28224762
Stereoisomerization of readily available all-cis-1,3,5,7-tetrahydroxy-1,3,5,7-tetraisobutylcyclotetrasiloxane (1 a) was carried out under acidic conditions to afford cis-trans-cis (1 b), all-trans (1 c), and cis-cis-trans (1 d) isomers. The compounds in the reaction mixture could be easily separated into 1 a and a mixture of 1 b, 1 c, and 1 d by the treatment with chloroform. Compounds 1 b, 1 c, and 1 d were further separated and isolated, and each structure was identified. The experimental results indicated that the most plausible mechanism is a substitution reaction at the silicon center via a pentacoordinate intermediate without a cyclic siloxane bond cleavage reaction. The obtained isomer 1 a or 1 b further reacted with dichlorodiphenylsilane in the presence of triethylamine to give syn-type laddersiloxane (2 a) or anti-type laddersiloxane (2 b), respectively.
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1
Colección:
01-internacional
Base de datos:
MEDLINE
Idioma:
En
Revista:
Chem Asian J
Año:
2017
Tipo del documento:
Article
País de afiliación:
Japón
Pais de publicación:
Alemania