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Identifier

000401673

Title

Αναγωγή αλκυνίων και βοριοσιλυλίωση κυκλικών αιθέρων καταλυόμενες από νανοσωματίδια Au

Alternative Title

Reduction of alkynes and silaboration of cyclic ethers catalyzed by gold nanoparticles

Author

Βασιλικογιαννάκη, Ελένη

Thesis advisor

Στρατάκης, Μανώλης

Reviewer

Κατερινόπουλος, Χαράλαμπος
Λυκάκης, Ιωάννης

Abstract

In the present thesis, new applications of gold nanoparticles as catalysts, supported on metal oxides surfaces were studied on a variety of organic transformations. Mechanistic studies were performed on each reaction. The results can be summarized as follows: -Supported gold nanoparticles on titania catalyze the selective hydrogenation of π-systems, in particular, the semihydrogenation of alkynes into alkenes with dimethylamine borane complex (Me₂NHBH₃, DMAB) as reductant, in excellent yields under mild conditions. Internal alkynes provide cis-alkenes, making this protocol an attractive alternative of the classical Lindlar’s hydrogenation. This protocol of stereoselective semihydrogenation of alkynes was applied in the efficient synthesis of a natural product, combretastatin A-4. -The silaboration of oxetanes and unactivated epoxides by dimethylphenylsilyl boronic ester of pinacol (Me₂PhSiBpin) catalyzed by Au/TiO₂ under mild conditions was studied. This transformation provides β-silyloxy or γ-silyloxy boronic esters. It is the first time that such transformation is reported in literature under any catalytic conditions. -The isomerization of 2,2-disubstituted oxetanes into homoallylic alcohols catalyzed by Au/TiO₂ was studied and presented for the first time in literature.

Language

Greek

Subject

Alkynes

Cis-alkenes

Cis-αλκένια

Epoxides

Heterogeneous catalysis

Homoallylic alcohols

Me2NHBH3

Me2PhSiBpin

Oxetanes