This cutting-edge research work presents a comprehensive and in-depth theoretical investigation on the mechanism, selectivity patterns, and ligand effects in gold(I)-catalyzed annulations between ynamides and isoxazoles.
The steric hindrance effect of the JohnPhosAu(MeCN)SbF6 ligand and the π–π stacking interaction between the phenyl group on the indole and the phenyl group of the ynamide enhance the selectivity towards the E-configuration in the reaction.
The work reports a bicyclic annulation of 1,5-diynamide with nitrone in the presence of gold catalyst. The key intermediate containing alkenylgold oxonium species (Int-5) leads to the [3+2] cycloaddition with nitrone to furnish bicyclic products.
The enantioselective Au(I)-catalyzed cyclization of bromo-1,5- and 1,6-enynes is reported. Mechanistic studies explain the formation of racemic cycloisomerization products from alkoxycyclization of bromo-1,6-enynes in the absence of a nucleophile.
A novel synthesis of 1,4- and 1,5-diketones based on a gold(I)-catalyzed hydration reaction is herein described. Application to chemoenzymatic cascades is also shown under mild conditions.