THESIS
2014
xiii, 139 pages : illustrations ; 30 cm
Abstract
Theoretical studies on the mechanism of transition metal mediated and catalyzed C-C
formation reactions involving CO
2 activation and cycloaddition and cycloisomerization are
reported in this thesis.
Part I: Theoretical studies of transition-metal mediated and catalyzed reactions involving
CO
2 have been reviewed in this chapter. Fundamental steps related to organometallic
reactions of CO
2 have been discussed, such as CO
2 insertion into an M-R bond, CO
2 insertion
into an M-X bond, and oxidative coupling with unsaturated organic substrates.
Part II: The mechanism of copper-catalyzed hydrocarboxylation of alkynes using CO
2 and
hydrosilanes has been studied. In addition to hydrocarboxylation of alkynes, hydrosilylation
of CO
2 and silacarboxylation of alkynes have also been investiga...[
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Theoretical studies on the mechanism of transition metal mediated and catalyzed C-C
formation reactions involving CO
2 activation and cycloaddition and cycloisomerization are
reported in this thesis.
Part I: Theoretical studies of transition-metal mediated and catalyzed reactions involving
CO
2 have been reviewed in this chapter. Fundamental steps related to organometallic
reactions of CO
2 have been discussed, such as CO
2 insertion into an M-R bond, CO
2 insertion
into an M-X bond, and oxidative coupling with unsaturated organic substrates.
Part II: The mechanism of copper-catalyzed hydrocarboxylation of alkynes using CO
2 and
hydrosilanes has been studied. In addition to hydrocarboxylation of alkynes, hydrosilylation
of CO
2 and silacarboxylation of alkynes have also been investigated and compared. Through
the studies, we are able to understand the reason why only hydrocarboxylation of alkynes has
been observed experimentally.
Part III: The reaction mechanism of dinuclear palladium(I) complexes containing two allyl
bridging ligands with CO
2 has been studied. The transformations of the first and second
bridging allyl ligand to the bridging carboxylate ligands have been compared. It is found that
the transformation of the first bridging allyl ligand is kinetically and thermodynamically
favorable, while the transformation of the second ligand is thermodynamically and kinetically
unfavorable.
Part IV: Gold-catalyzed cycloisomerization of 1,5-enynes has been investigated. How
substituents influence the reaction paths in the cycloisomerization of 1,5-enynes catalyzed by
AuCl and [AuL]
+ (L = phosphine) has been examined and discussed.
Part V: The reaction mechanism of rhodium-mediated [3+2] cycloaddition reactions of
diynes has been investigated. It was found that the regioselectivity in the reactions of
unsymmetrical diynes is determined by the nucleophilicity of the distal alkyne carbon in a
pseudo octahedral complex and the stability of a zwitterionic intermediate.
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