Catalytic reductive cyclisations of amides using Vaska's complex

Chapter 1 introduces tertiary amines, and the main strategies available for their synthesis. Vaska’s complex is introduced, and its recent use for the reduction of tertiary amides and lactams is exhaustively described. Chapter 2 details the development of a spirocyclisation methodology from indole-tethered tertiary amides and lactams. The selectivity observed and the broad substrate scope make it a method of choice for the synthesis of spirocyclic indolines. Chapter 3 describes the development of a cycloaddition methodology, based on accessing azomethine ylides from tertiary amides and lactams, and reacting these 1,3-dipoles with a range of dipolarophiles, generating polycyclic amines. It is of value for the synthesis of polysubstituted pyrrolidine ring-containing amines. Chapter 4 details the investigations towards the design and application of a synthetic sequence leading to the total synthesis of a pentacyclic alkaloid, catharanthine. Previous syntheses are described, before model studies establish the feasibility of an IMDA cascade sequence triggered with Vaska’s complex. The natural product synthesis is then described. Chapter 5 details our efforts towards making the previously described methodologies amenable to large scale, and why they should be particularly attractive for industrial applications. Finally, preliminary results for the synthesis of new Vaska-type Iridium complexes for the reduction of non-tertiary amides functional groups are described.