Synthetic Studies toward Gold(I)-catalyzed preparation of Trifluoromethyl Compounds
Abstract
In this project gold(I)-catalyzed reactions on triple bonds has been investigated, with the trifluoromethyl group incorporated. Initially the goal was to develop a new gold(I)-catalyzed trifluoromethylation reaction, as shown below. This goal has not been reached. Several attempts in order to prepare a trifluoromethylated di-hydropyran derivate, both by direct trifluoromethylation and via trifluoromethylated precursors. A study of the reactivity of a trifluoromethylated alkyne in regard to gold(I)-catalysis has been performed in order to obtain a better understanding of reactions on similar substrates. The study has been performed by GLC analysis of a range of small scale reactions, as shown below, performed under different conditions. The study showed that the nucleophilic attack on the gold activated \ce{CF3}-alkyne triple bond is highly favored towards generating a vinyl compound. While terminal alkynes react further to form unsaturated products, the trifluoromethyl substrate is fairly stable at the alkene stage, although it will react further given tougher conditions. NMR has been essential for the structure elucidation and monitoring of reactions throughout the project.