Complete Field Guide to Asymmetric BINOL-Phosphate Derived Brønsted Acid and Metal Catalysis: History and Classification by Mode of Activation; Brønsted Acidity, Hydrogen Bonding, Ion Pairing, and Metal Phosphates

1.1. General Reactivity of Alkyne-Gold(I) Complexes
For centuries, gold had been considered a precious, purely decorative inert metal. It was not until 1986 that Ito and Hayashi described the first application of gold(I) in homogeneous catalysis.1 More than one decade later, the first examples of gold(I) activation of alkynes were reported by Teles2 and Tanaka,3 revealing the potential of gold(I) in organic synthesis. Now, gold(I) complexes are the most effective catalysts for the electrophilic activation of alkynes under homogeneous conditions, and a broad range of versatile synthetic tools have been developed for the construction of carbon–carbon or carbon–heteroatom bonds.

Gold(I) complexes selectively activate π-bonds of alkynes in complex molecular settings,4−10 which has been attributed to relativistic effects.11−13 In general, no other electrophilic late transition metal shows the breadth of synthetic applications of homogeneous gold(I) catalysts, although in occasions less Lewis acidic Pt(II) or Ag(I) complexes can be used as an alternative,9,10,14,15 particularly in the context of the activation of alkenes.16,17 Highly electrophilic Ga(III)18−22 and In(III)23,24 salts can also be used as catalysts, although often higher catalyst loadings are required.

In general, the nucleophilic Markovnikov attack to η2-[AuL]+-activated alkynes 1 forms trans-alkenyl-gold complexes 2 as intermediates (Scheme 1).4,5a,9,10,12,25−29 This activation mode also occurs in gold-catalyzed cycloisomerizations of 1,n-enynes and in hydroarylation reactions, in which the alkene or the arene act as the nucleophile.



Scheme 1

Anti-Nucleophilic Attack to η2-[AuL]+-Activated Alkynes

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Gold(I)-Catalyzed Activation of Alkynes for the Construction of Molecular Complexity

Some Typical Advances in the Synthetic Applications of Allenes

Dialkylbiaryl phosphines are a valuable class of ligand for Pd-catalyzed amination reactions and have been applied in a range of contexts. This perspective attempts to aid the reader in the selection of the best choice of reaction conditions and ligand of this class for the most commonly encountered and practically important substrate combinations.

Dialkylbiaryl phosphines in Pd-catalyzed amination: a user's guide

Good Partnership between Sulfur and Fluorine: Sulfur-Based Fluorination and Fluoroalkylation Reagents for Organic Synthesis

From 2000 to mid-2010: a fruitful decade for the synthesis of pyrazoles.

Olefin metathesis reactions with fluorinated substrates, catalysts, and solvents.

Gold-catalyzed intramolecular hydroamination of o-alkynylbenzyl carbamates: a route to chiral fluorinated isoindoline and isoquinoline derivatives.

N-Sulfinyl amines have been successfully employed as nitrogen nucleophiles for the asymmetric intramolecular aza-Michael reaction. The synthetic strategy involves a cross-metathesis reaction followed by the Michael-type cyclization, either in a base-catalyzed two-step procedure or in a tandem fashion. The developed methodology allows access to chiral substituted pyrrolidines and piperidines bearing one or two stereocenters and it has been applied to the synthesis of the piperidine alkaloid (-)-pinidinol.

Pablo Barrio

Papers

From 2000 to mid-2010: a fruitful decade for the synthesis of pyrazoles.

Olefin metathesis reactions with fluorinated substrates, catalysts, and solvents.

Gold-catalyzed intramolecular hydroamination of o-alkynylbenzyl carbamates: a route to chiral fluorinated isoindoline and isoquinoline derivatives.

N‐Sulfinyl Amines as a Nitrogen Source in the Asymmetric Intramolecular Aza‐Michael Reaction: Total Synthesis of (−)‐Pinidinol

Tandem Nucleophilic Addition−Intramolecular Aza-Michael Reaction: Facile Synthesis of Chiral Fluorinated Isoindolines