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Stereoisomers of 1,3,5,7-Tetrahydroxy-1,3,5,7-tetraisopropylcyclotetrasiloxane: Synthesis and Structures in the Crystal.
- Source :
-
Journal of the American Chemical Society . 2/23/2005, Vol. 127 Issue 7, p2256-2263. 8p. - Publication Year :
- 2005
-
Abstract
- The first synthesis of all four stereoisomers of 1 ,3,5,7-tetrahydroxy-1,3,5,7-tetraisopropylcyclotetrasiloxane, [i-PrSiO(OH)]4 (all-trans-, cis-cis-trans-, cis-trans-cis-, and all-cis-1), is presented. The starting compounds, all-trans-, cis-cis-trans, cis-trans-cis-, and all-cis-1,3,5,7-tetraaryl-1,3,5,7-tetraisopropylcyclotetrasiloxanes, were prepared by the hydrolysis of the corresponding arylisopropyldichlorosilanes, i-PrArSiCl2 (Ar = Ph, p-tolyl), and subsequent separation of isomers. A combination of dephenylchlorination of tetraarylcyclotetrasiloxanes and the following hydrolysis proved to be an efficient method for the stereospecific transformation of aryl-substituted cyclotetrasiloxanes into (i-PrSiO(OH))4. For example, treatment of cis-trans-cis-1,3,5,7-tetraphenyl-1,3,5,7-tetraisopropylcyclotetrasilane with HCl and AlCl3, followed by hydrolysis in the presence of pyridine, resulted in the exclusive formation of cis-trans-cis-1 in 92% yield. The structures of cis-cis-trans-1, cis-trans-cis-1, and all-cis-1 were determined by X-ray crystallography. All isomers were found to construct unique packing structures by intermolecular hydrogen bonding; cis-trans-cis-1 composed an infinite antiladder structure, and cis-cis-trans-1 formed a sheetlike structure. [ABSTRACT FROM AUTHOR]
- Subjects :
- *STEREOISOMERS
*STEREOCHEMISTRY
*HYDROLYSIS
*CRYSTALLOGRAPHY
*SOLVOLYSIS
*CHEMISTRY
Subjects
Details
- Language :
- English
- ISSN :
- 00027863
- Volume :
- 127
- Issue :
- 7
- Database :
- Academic Search Index
- Journal :
- Journal of the American Chemical Society
- Publication Type :
- Academic Journal
- Accession number :
- 16249969
- Full Text :
- https://doi.org/10.1021/ja043894m