Development of Gold(I)-Catalyzed Reactions Between Alkenes and Acetylene Gas

Identifier:  TDX:4605

Handle: https://hdl.handle.net/20.500.11797/TDX4605

Authors:  Medina Gil, Tania

Abstract:
Gold(I) catalysis has experienced a huge development over the past decades. However, this advances have been restricted mostly to the intramolecular reactions between alkynes and alkenes. The intermolecular version of these reactions remains underdeveloped. Moreover, acetylene is one of the most important feedstock in chemical production. Despite this, its use in chemistry industry is limited to vinylation processes or non-catalyzed hydrochlorination reactions. In this Doctoral Thesis, the development of gold(I)-catalyzed intermolecular reactions between alkenes and acetylene gas is presented. Firstly, an unprecedented gold(I)-catalyzed aryloxyvinylation reaction between allylphenols and acetylene gas was studied. A wide variety of 3-vinyl chromanes was prepared in good yields and functional group tolerance. The applicability of this methodology was demonstrated by the late stage functionalization of lapachol natural product and several diversifications of the model product. Additionally, the enantioselective version of this reaction was initially explored for the first enantioselective activation of acetylene under gold catalysis. Inspired by these results we were interested on the development of a fully intermolecular alkoxyvinylation reaction with acetylene gas where neither the alkene, alkyne nor the alcohol where covalently linked. After a deep screening of possible substrates, we found out N-vinyl benzamides as suitable substrates for the synthesis of vinyl hemiaminal products. The moderate yields obtained are due to the presence of secondary polymerization processes that were studied in detailed for a model reaction. Finally, an innovative gold(I)-catalyzed method for the functionalization of 2-alkylated indoles with acetylene gas was investigated. A myriad of biscyclopropanated indoles was prepared in moderate to good yields. Additionally, DFT calculations were performed to gain insights into the reaction mechanism.