Transition metal catalyzed carbon-carbon bond forming reactions. Stereoselective synthesis of conjugated dienoic and trienoic esters via alkyne elementometalation- Palladium catalyzed cross-coupling

• Main Author: Mohan, Swathi
• Format: Dissertation
• Language: English
• Published: ProQuest Dissertations & Theses 01-01-2010
• Subjects: Organic chemistry
• ISBN: 9781124612355; 1124612351

The first chapter gives a general account of the history of organometallic chemistry and the also discusses the importance of d-block transition metals and its usefulness in the development of cross-coupling. The chapter shows the usefulness of Pd-catalyzed cross-coupling in carbon-carbon bond formation and its general scope. The next chapter, alkenyl-alkenyl cross-coupling by Negishi alkenylation lead to the stereoselective synthesis of all possible isomers of dienoic and trienoic esters via Alkyne Elementometalation–Pd catalyzed cross-coupling tandem process in the presence of PEPPSI catalyst. The synthesis of dienes by Negishi coupling was also compared with other methods such as carbonyl olefination (HWE and SG), Heck alkenylation and Suzuki coupling. Pd-catalyzed alkenylation–carbonyl olefination synergistic approach was used in the synthesis of some isomers of trienoic esters. In the last chapter, emphasis is given towards exploring high turnover numbers (TONs) in Pd-catalyzed alkenyl-alkenyl cross-coupling. Negishi coupling between alkenylzirconium species and alkenyl halide lead to the TONs in the range of 105-107. This will help lower the catalyst loading and reduce the cost in large scale industrial applications of Pd-catalyzed cross-coupling reactions.