Comprehensive Overview of Homogeneous Gold-Catalyzed Transformations of π-Systems for Application Scientists

Abstract

We present an overview of fundamental catalytic reactions of nucleophiles with π-systems in relation to gold chemistry. We present examples of reactions with gold-activated π-systems, alkynyl or allenyl moieties, and the regulation of their reactivity due to the presence of an electron-donating or -withdrawing group. The reactions describe furnished hard-to-reach heterocyclic building blocks for medicinal chemistry purposes. Important gold(I) or gold(III) complexes that are used as catalysts are presented. We examine the activation of such π-systems using gold(I) or gold(III) catalysts and the corresponding divergent catalytic transformations. We provide examples of divergent catalysis using gold(I) catalyst and other metal catalysts (Pt, Ag, Pd, Rh, Sc, Cu) or by changing the ligands in gold(I) catalyst complexes. We also discuss the role of the solvent, counterions and additives in gold(I)-catalyzed reactions. We mention, in a few cases, characteristic experimental or computational studies of these gold-catalyzed reactions of nucleophiles with π-systems.

Recent Advances on the Catalytic Asymmetric Allylic α-Alkylation of Carbonyl Derivatives Using Free Allylic Alcohols

“…Some years ago, the use of soft π-Lewis acids, mainly cationic gold complexes, for the activation of alkenes and other substrates containing π-bonds received much attention. 34 In this regard, allylic alcohols have been a class of substrates, among others, upon which these Au catalysts have been applied in order to perform the allylic substitution reaction.…”

Metal-catalyzed Markovnikov-type selective hydrofunctionalization of terminal alkynes

“…Currently, there are two main modes for synthesizing alkenyl halides from alkynes. 165–168 The first is to use low-valent metals with strong reducing properties to be oxidized by H–X bond in acids, such as hydrochloric acid, hydrobromic acid, and hydriodic acid, to form new metal–hydride bonds and metal–halogen bonds. Alkynes are then inserted into the metal–hydrogen bonds to generate the corresponding alkenyl metal compounds then undergo reductive elimination to obtain α-alkenyl halides (as shown in mode a, Scheme 2).…”