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Master's Dissertation
DOI
10.11606/D.46.1988.tde-09092011-113001
Document
Author
Full name
Helio Alexandre Stefani
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
São Paulo, 1988
Supervisor
Committee
Comasseto, Joao Valdir (President)
Ferreira, Jose Tercio Barbosa
Marzorati, Liliana
Title in Portuguese
Reagentes de selênio e telúrio em síntese orgânica: íons de carbênio estalizados por selênio e alfa-telurocetonas
Keywords in Portuguese
Alfa-Selenofenil acetaldeídos
Cetonas
Reagentes orgânicos
Selênio
Síntese orgânica
Telúrio
Telurocetonas
Abstract in Portuguese
Na primeira parte deste trabalho, desenvolvemos duas metodologias para a preparação de α-dicloroteluro cetonas. A primeira utiliza a reação direta de tricloretos de ariltelúrio com cetonas e a segunda envolve a reação do mesmo reagente com éteres enólicos de silício de cetonas. As dicloroteluro cetonas preparadas foram transformadas em α-halo cetonas pela reação com cloro ou bromo, ou utilizando condições de termólise sob pressão reduzida. Dados de ressonância magnética nuclear de 1H e de 13C, de difração de raios-X e de espectros no infra-vermelho foram utilizados na determinação estrutural dos compostos preparados. Numa segunda arte foram preparados α-halo-α-seleno alcanos através da adição de HBr a selenetos vinílicos obtidos por reação de acetilenos aromáticos com selenofenol. Os α-halo-α-seleno alcanos foram transformados em α-selenofenil acetaldeídos por reação de solvólise em DMSO.
Title in English
Selenium and Tellurium in Organic Synthesis: Carbenium Ions Stabilized of Selenium and Alfa-Teluroketones
Keywords in English
Alfa-Selenophenyl acetaldheydes
Ketones
Organic reagents
Organic synthesis
Tellurium
Telluroketonas
Abstract in English
In the first parto of this work two methodologies for the synthesis of α-dichlorotelluroketones were developed. The first one employs the reaction of aryltellurium tricholorides with ketones and the second one involves the reaction of the same reagent with silylenol ethers of ketones. The α-dichlorotelluroketones prepared were transformed into α-halo ketones by means of the reaction with chlorine or bromine or by pyrolysis at reduced pressure. 1H and 13C nuclear magnetic ressonance, x-ray difraction and infrared data were used in the structure elucidations of the compounds prepared. In the second part of the work α-halo- α-seleno-alkanes were prepared by addition of hydrogen bromide to vinylic selenides which were prepared by reacting aromatic acetylenes with selenophenol. The α-halo-α-seleno-alkanes were transformed into α-selenophenyl acetaldehydes by solvolysis in DMSO.
 
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Mestrado_HAS.pdf (4.36 Mbytes)
Publishing Date
2011-09-23
 
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