Stereoelectronic requirement and effect of ring size on silanol elimination: a kinetic study

Autor:	Gopalpur Nagendrappa, M. Narendra Mallya
Rok vydání:	2001
Předmět:	Ring size Silanol chemistry.chemical_compound Hydrolysis Reaction rate constant Hydrogen bond Chemistry Intramolecular force Alkane stereochemistry Physical chemistry Organic chemistry Ring (chemistry)
Zdroj:	Journal of the Chemical Society, Perkin Transactions 2. :2248-2252
ISSN:	1364-5471 1472-779X
DOI:	10.1039/b108237j
Popis:	Acid catalyzed elimination of silanol from the cyclic cis-α,β-dihydroxysilanes 3–8 to cycloalkanones was studied at three different temperatures (298, 313 and 328 K). Silyldiols 3–7 hydrolyzed smoothly, while 8 was resistant to hydrolysis. The observed ease of elimination (reflected in the rate constants) was found to be related to the conformational flexibility of the ring and intramolecular hydrogen bonding. The results have confirmed the requirement of perfect antiperiplanar geometry of the eliminating groups, SiMe3 and β-OH. The quantitation of the hydrolysis products, the cycloalkanones, was done using the gas chromatographic peak area normalization method using an internal standard. The rate data obtained at three different temperatures were employed to calculate ΔH‡, ΔS‡, and ΔG‡. The rate constants and thermodynamic parameters increase with the ring size. There is an interesting demarcation between these two values for common ring silyldiols and the larger ring silyldiols.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::b5413c3be9f178d345d98c256a9ee20e https://doi.org/10.1039/b108237j Zobrazit plný text záznamu