Gold(I)-Catalyzed Cycloadditions and their Application in the Synthesis of Natural Products

Identifier:  TDX:3260

Handle: https://hdl.handle.net/20.500.11797/TDX3260

Authors:  Armengol i Relats, Helena

Abstract:
The potential of gold(I) catalysis on the synthesis of natural products has been widely explored in the last decades. This Doctoral Thesis presents our efforts to expand the applications of gold(I)-catalyzed cycloadditions on total synthesis. First, we have developed a new methodology for acetylene activation by means of gold(I) catalysis, in which the ligand on the gold(I) catalyst can tune the reaction outcome, either for the formation of (Z,Z)-1,3-dienes or towards bis-cyclopropanes. This method was applied to the one-step total synthesis of waitziacuminone. In second place, we have established a novel cycloisomerization/cycloaddition cascade which allows for the rapid and efficient construction of hydroazulenes and divinylcyclopropanes, from enynes and dienes. The mechanism was studied experimentally and computationally, finding a strong dependence on the nature of the diene and on the gold(I) catalyst employed, for the reaction outcome. Finally, this strategy was applied to a common synthetic route towards aspterric acid, penigrisacid A and schisanwilsonene A. The carbon-skeletons of the three natural products were synthesized and characterized by x-ray diffraction.