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Identifier 000034375
Title Ασύμμετρες φωτοξειδώσεις χειρόμορφων αλκενίων προσροφημένων σε ζεόλιθο Na-Y
Author Κοσμάς, Γιάννης
Thesis advisor Στρατάκης, Μανώλης
Abstract This project entails a preliminary research on the possibility of obtaining asymmetric induction of the ene hydroperoxidation reactions in the photooxygenation of chiral alkenes within zeolite Na-Y. The relative stereoselectivity and diastereoselectivity were measured though stereiosotopic labeling of the methyl groups of the alkenes. The conclusions can be summarized as follows: 1. The photooxygenation of the alkenes, which bear a sterogenic center at the a- position in respect to the double bond, do not induce an asymmetric induction for the reaction within the Na-Y zeolite. On the contrary this reaction in solution affords mainly the erythro diastereomer relative to the threo. These results were explained in correlation with the more stable structures which appear to arise from the interaction of the alkenes with the Na+ cations of the interior of the zeolite supercage. 2. On the other hand the chiral alkene 2-methyl-5-phenyl-2-hexene in which the stereogenic center is in a β-position with respect to the double bond, while exhibiting a very poor diastereoselectivity (~10%) when the reaction takes place in a solution, shows a significant enhancement of product regioselectivity and diastereoselectivity when reacting within the thionin-supported zeolite. When the reaction occurs in the more substituted side of the double bond the diastereoselectivity is increased to 55% d.e. while at the less substituted side is poor (18%). These results can be explained based on the confinement of the molecule within the cages of the zeolite and to the cation - interaction as well.
Language Greek
Issue date 2001-07-01
Collection   School/Department--School of Sciences and Engineering--Department of Chemistry--Post-graduate theses
  Type of Work--Post-graduate theses
Permanent Link https://elocus.lib.uoc.gr//dlib/1/9/3/metadata-dlib-2001MST0709.tkl Bookmark and Share
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