TRANSITION METAL-CATALYZED CARBON-CARBON AND CARBON-NITROGEN BOND FORMATION AND ASYMMETRIC CATALYSIS WITH BISOXAZOLIDINE LIGANDS
Palladium-phosphinous acids and chlorophosphine analogues have attracted increasing interest due to their high catalytic activity in various organic transformations, long shelf-life and facile handling. In this thesis, it is reported that these catalysts are very useful in Negishi cross-couplings of aryl or acyl halides with aliphatic and aromatic organozinc reagents. Similarly, palladium-phosphinous acids were employed in the formation of sterically hindered biaryls exhibiting at least two ortho substituents from aryl halides and aryl Grignard reagents.Due to an ever-increasing demand of inexpensive and environmentally friendly carbon-nitrogen bond formation protocols for large-scale industrial applications, copper-catalyzed amination has emerged as an important synthetic strategy. A highly efficient Cu 2O-catalyzed C-N bond formation protocol suitable to amination of aryl halides with ammonia, amines and amides was developed. This reaction tolerates a wide range of functional groups and provides a wide range of C-N coupling products in up to 99% yield. The chemoselectivity, experimental simplicity, and the low cost of the catalytic system are quite remarkable.In addition to the widely explored oxazolines ligands, oxazolidines bearing a nonplanar, sterically more demanding saturated scaffold have been applied to various asymmetric reactions in recent years. A highly enantioselective copper-bisoxazolidine catalyzed nitroaldol reaction with aliphatic and aromatic trifluoromethyl ketones and alpha-keto esters was developed to provide a wide range of functionalized chiral tertiary alcohols. Finally, a practical enantioselective synthesis of N-substituted 1,3-diaminopropanols via copper-bisoxazolidine catalyzed nitroaldol reaction of alpha-keto amides and subsequent reduction of the nitro and amide groups was introduced. This route involves the first catalytic asymmetric intermolecular carbon-carbon bond formation with alpha-keto amides.
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