Selective carbon -carbon and carbon -heteroatom bond formation reactions catalyzed by silver, copper, palladium, ruthenium, and zinc, and their application to the synthesis of natural products

In this thesis work, an extensive study was carried out on the synthesis of alkynes via Pd-catalyzed cross-coupling reactions. Sonogashira and Negishi\u27s reactions were considerably scrutinized and compared. In the course of this study the superiority of alkynylzincs emerged in several critical cases, and new protocols for the use of alkynylzincs were developed. This reaction was also combined with a metal catalyzed cyclization reaction to selectively form δ-pyrones and/or γ-butenolides. An extensive study on the scope of this reaction showed that under ZnBr2 catalysis the formation of δ-pyrones is favored, and in many cases highly selective. On the other hand Ag 2CO3 catalysis constantly favors the formation of γ-butenolides with very high selectivity. A third part of this thesis focuses on the use of palladium-catalyzed cross-coupling reactions for the synthesis of stereodefined tetrasubstituted olefins and its application to the synthesis of two stereoisomeric natural products, (E)- and (Z)-γ-bisabolenes. Further work includes the palladium catalyzed tandem carbonylation-cyclization reaction and its use for the synthesis of two natural products, frullanolide and arbusculin B. The final chapter discusses some most recent results on the zirconium-catalyzed enantioselective carboalumination and its application to the synthesis of fluvirucinine A1