Part I: Development of New Methods for Application in Multicatalytic Reactions Part II: Investigation of Stable Carbenium Catalysts as Hydride Transfer Agents

摘要

Part I of this thesis focuses on the development of novel synthetic methods and investigations into their incorporation into multicatalytic reactions. The first chapter describes the development of a bismuth(III)triflate catalyzed hydrocarboxylation reaction of unactivated alkenes to synthesize lactones. Efforts toward applying this new methodology in multicatalytic sequences are described. In the second chapter, the development of palladium(II) mediated oxidative formylation and ketonylation methods to construct complex aldehydes and ketones is presented. Investigations into the oxidative formylation mechanism revealed the formation of a stable acylpalladium hydride intermediate that could be manipulated in situ allowing for the formation of other functionality. These methods were shown to be compatible in multi-transformation processes leading to the synthesis of complex heterocyclic products in a single reaction vessel. The third chapter describes the total synthesis of members of the Tylophora alkaloid family of molecules using a key oxidative carbonylation step. Application of a tandem palladium(II) catalyzed aminochlorocarbonylation / indium(III) catalyzed Friedel-Crafts acylation led to the rapid construction of the key intermediate in these syntheses in a one-pot reaction. The concise syntheses of both 13a,alpha-secoantofine and antofine using this multicatalytic strategy are presented. The second part of this thesis describes the study of stable carbocations as catalysts for hydride transfer reactions. Both cyclopropenium and trityl catalysts are investigated in a reductive etherification method. A study of trityl catalyst structure and initial investigations into the development of chiral trityl catalysts are presented.