https://pubs.rsc.org/en/content/articlepdf/2019/NP/C8NP00092A

Marine natural products.

Although homogeneous gold catalysis was known previously, an exponential growth was only induced 12 years ago. The key findings which induce that rise of the field are discussed. This includes early reactions of allenes and furanynes and intermediates of these conversions as well as hydroarylation reactions. Other substrate types addressed are alkynyl epoxides and N-propargyl carboxamides. Important vinylgold intermediates, the transmetalation from gold to other transition metals, the development of new ligands for gold catalysis, and significant contributions from computational chemistry are other crucial points for the field highlighted here.

Gold-Catalyzed Organic Reactions

N-Heterocyclic Carbenes in Late Transition Metal Catalysis

The ability of platinum and gold catalysts to effect powerful atom-economic transformations has led to a marked increase in their utilization. The quite remarkable correlation of their catalytic behavior with the available structural data, coordination chemistry, and organometallic reactivity patterns, including relativistic effects, allows the underlying principles of catalytic carbophilic activation by π acids to be formulated. The spectrum of reactivity extends beyond their utility as catalytic and benign alternatives to conventional stoichiometric π acids. The resulting reactivity profile allows this entire field of catalysis to be rationalized, and brings together the apparently disparate electrophilic metal carbene and nonclassical carbocation explanations. The advances in coupling, cycloisomerization, and structural reorganization—from the design of new transformations to the improvement to known reactions—are highlighted in this Review. The application of platinum- and gold-catalyzed transformations in natural product synthesis is also discussed.

Catalytic Carbophilic Activation: Catalysis by Platinum and Gold π Acids

Stronger Brønsted acids

This account provides a comprehensive overview of the development of gold and platinum catalysis of the enyne cycloisomerization. The use of these soft, alkynophilic metals enables mild, chemoselective and efficient transformations of a variety of readily available acyclic enynes to a wide range of synthetically useful carbocyclic and heterocyclic products. The review is organized according to diverse structural types of enynes that undergo skeletal cycloisomerizations. The account begins with an overview of transformations of primarily 1,6-enynes to 1-alkenylcyclopentenes, bicyclo[4.1.0]heptenes, methylenecycloalkenes, bicyclo[4.3.0]nonadienes and bicyclo[3.2.0]heptenes. This section is followed by the discussion of cycloisomerizations of 1,5-enynes, which enable a rapid access to a range of other cyclic products, including bicyclo[3.1.0]hexenes, cyclohexadienes, heterobicycloalkenes, methylenecyclopentenes, naphthalenes and methyleneindenes. In addition, the [3,3] rearrangement of 1,5-enynes provides efficient access to the corresponding allenes. The account concludes with an overview of the most recent studies on gold- and platinum-catalyzed cycloisomerizations of 1,4- and 1,3-enynes. Due to the rapidly increasing interest in this area during the past three to five years, we believe that this review provides a timely and comprehensive discussion of the development gold- and platinum-catalyzed cycloisomerization starting from the initial pioneering investigations to the latest advances in the field. A significant emphasis is placed on the mechanistic discussion of the observed manifolds of skeletal reorganizations.

Gold and platinum catalysis of enyne cycloisomerization

For the past dozen years, homogeneous gold catalysis has evolved from a little known topic in organic synthesis to a fully blown research field of significant importance to synthetic practitioners, due to its novel reactivities and reaction modes. Cationic gold(I) complexes are powerful soft Lewis acids that can activate alkynes and allenes toward efficient attack by nucleophiles, leading to the generation of alkenyl gold intermediates. Some of the most versatile aspects of gold catalysis involve the generation of gold carbene intermediates, which occurs through the approach of an electrophile to the distal end of the alkenyl gold moiety, and their diverse transformations thereafter. On the other hand, α-oxo metal carbene/carbenoids are highly versatile intermediates in organic synthesis and can undergo various synthetically challenging yet highly valuable transformations such as C–H insertion, ylide formation, and cyclopropanation reactions. Metal-catalyzed dediazotizations of diazo carbonyl compounds ar...

https://escholarship.org/content/qt0pg244j3/qt0pg244j3.pdf?t=r15td1

A Non-Diazo Approach to α-Oxo Gold Carbenes via Gold-Catalyzed Alkyne Oxidation

Phenols are widely used as starting materials in both industrial and academic society. Dearomatization reactions of phenols provide an efficient way to construct highly functionalized cyclohexadienones. The main challenge to make them asymmetric by catalytic methods is to control the selectivity while overcoming the loss of aromaticity. In this tutorial review, an up to date summary of recent progress in CADA reactions of phenol and aniline derivatives is presented.

/pdf/catalytic-asymmetric-dearomatization-cada-reactions-of-2shyj51rq6.pdf

Catalytic asymmetric dearomatization (CADA) reactions of phenol and aniline derivatives

The treatment of readily available propargylic indole-3-acetates with a catalytic amount of AuCl(PPh3)/AgSbF6 leads to tandem activations of the propargylic esters and the in situ generated allenylic esters, resulting in expeditious access to highly functionalized cyclobutanes with fused 2,3-indoline and γ-lactone rings and an exocyclic E-double bond through sequential 3,3-rearrangement and [2 + 2] cyclization.

Tandem Au-catalyzed 3,3-rearrangement-[2 + 2] cycloadditions of propargylic esters : Expeditious access to highly functionalized 2,3-indoline-fused cyclobutanes

Homogeneous carboamination, carboalkoxylation and carbolactonization of terminal alkenes are realized via oxidative gold catalysis, providing expedient access to various substituted N- or O-heterocycles. Deuterium-labeling studies established the anti nature of the alkene functionalization and the indispensible role of Au(I)/Au(III) catalysis. This study constitutes the first example of catalytically converting C(sp3)−Au bonds into C(sp3)−-C(sp2) bonds in a cross-coupling manner and opens new opportunities to study gold alkene catalysis where alkylgold intermediates can be readily functionalized intermolecularly.

Liming Zhang

Papers

Gold and platinum catalysis of enyne cycloisomerization

A Non-Diazo Approach to α-Oxo Gold Carbenes via Gold-Catalyzed Alkyne Oxidation

Catalytic asymmetric dearomatization (CADA) reactions of phenol and aniline derivatives

Tandem Au-catalyzed 3,3-rearrangement-[2 + 2] cycloadditions of propargylic esters : Expeditious access to highly functionalized 2,3-indoline-fused cyclobutanes

Homogeneous gold-catalyzed oxidative carboheterofunctionalization of alkenes.