2.1. Oxygen Nucleophiles 3174 2.2. Nitrogen Nucleophiles 3177 3. Ag(I)-Mediated Addition of Nucleophiles to Allenes 3178 3.1. Oxygen Nucleophiles 3178 3.1.1. Allenic Alcohols 3178 3.1.2. Allenic Aldehydes and Ketones 3179 3.1.3. Allenic Acids 3180 3.2. Nitrogen Nucleophiles 3180 3.2.1. Allenic Amines 3180 3.2.2. Allenic Sulfonamides 3182 3.2.3. Allenic Carbamates 3182 3.2.4. Allenic Amides 3182 3.2.5. Allenic Oximes 3183 4. Ag(I)-Mediated Additions to Alkenes 3183 5. Ag(I)-Mediated Cycloaddition Reactions 3185 5.1. 1,3-Dipolar Cycloaddition Reactions of Azomethine Ylides 3185

Silver-mediated synthesis of heterocycles.

Ag-mediated reactions: coupling and heterocyclization reactions.

An efficient and versatile tandem process of acetalization and cycloisomerization reactions has been developed for the reactions of 1-alkynyl-2-carbonylquinoline substrates. The reaction occurs thanks to AuI and AgI catalysis. Silver(I) catalysis has been extensively studied (11 different silver species) on a broad range of quinoline derivatives (variation of alkyne substituent, of carbonyl function and of nucleophiles), leading to a variety of furoquinoline and pyranoquinoline moieties. An insight is given for the presumed mechanism along with DFT-B3 LYP/6–31G** calculations to address the 6-endo and 5-exo regioselectivities observed.

Silver versus Gold Catalysis in Tandem Reactions of Carbonyl Functions onto Alkynes: A Versatile Access to Furoquinoline and Pyranoquinoline Cores

Alkynols and alkyndiols represent excellent building blocks for oxycyclization reactions, leading to a large number of different cyclic structures in one single step. Recently, the use of gold salts and gold complexes has been introduced as an alternative to the traditional methods, providing mild reaction conditions and high group compatibility. This overview focuses on the most recent achievements on gold-catalyzed oxycyclizations, both from alkynols and alkyndiols, and their use in different cascade processes and total synthesis.

/pdf/gold-catalyzed-oxycyclizations-of-alkynols-and-alkyndiols-1o6ptwwhma.pdf

Gold catalyzed oxycyclizations of alkynols and alkyndiols

Synthesis of γ-Benzopyranone by TfOH-Promoted Regioselective Cyclization of o-Alkynoylphenols

Silver(I) ion catalysed intramolecular cyclisation of R′C6H4CCCOC6H3(OH)R (1a–d) at room temperature gives the corresponding aurone (2a–d) as the major product with a trace amount of the flavone; compounds (1a–d) could be prepared by the addition of the corresponding lithium acetylide (4a–b) to the substituted salicyl aldehyde (5a–c), followed by MnO2 oxidation.

Shang-Jen Leu

Papers

Intramolecular cyclisation catalysed by silver(I) ion; a convenient synthesis of aurones