Ynamides are unique alkynes with a carbon-carbon triple bond directly attached to the nitrogen atom bearing an electron-withdrawing group. The alkyne is strongly polarized by the electron-donating nitrogen atom, but its high reactivity can be finely tempered by the electron-withdrawing group. Accordingly, ynamides are endowed with both nucleophilic and electrophilic properties and their chemistry has been an active research field. The catalytic intermolecular annulations of ynamides, featuring divergent assembly of structurally important amino-heterocycles in a regioselective manner, have gained much attention over the past decade. This review aims to provide a comprehensive summary of the advances achieved in this area involving transition metal and acid catalysis. Moreover, the intermolecular annulations of ynamide analogs including ynol ethers and thioalkynes are also discussed, which can provide insights into the reactivity difference caused by the heteroatoms.

Reactivity of ynamides in catalytic intermolecular annulations.

Tandem reactions using base-promoted processes have been developed for the synthesis of xanthone and chromone derivatives. The first examples of base-promoted insertion reactions of isolated carbon-carbon triple bonds into carbon-carbon σ-bonds have been reported. Using these approaches, polycyclic structures can be prepared. This reaction has the potential to become a general synthetic protocol for the preparation of multi-substituted xanthones and chromones due to the abundance of easily accessible starting materials possessing diverse substituent groups.

Base-Promoted Tandem Reaction Involving Insertion into Carbon-Carbon σ-Bonds: Synthesis of Xanthone and Chromone Derivatives.

Regioselective synthesis of 3,4-disubstituted isocoumarins through the Pd-catalyzed annulation of 2-iodoaromatic acids with ynamides

Metal-Free [2 + 2 + 2] Cycloaddition of Ynamides with Nitriles to Construct 2,4-Diaminopyridines

Zn(II)-Catalyzed One-Pot Synthesis of Coumarins from Ynamides and Salicylaldehydes.

Synthesis of 3-Substituted 2-Aminochromones via Sn(IV)-Promoted Annulation of Ynamides with 2-Methoxyaroyl Chlorides

A Sn(IV)-promoted annulation reaction of ynamides is described for the efficient synthesis of 3-substituted 2-aminochromones under mild conditions. This novel method allows for a concomitant construction of C–C and C–O bonds between ynamides and 2-methoxyaroyl chlorides by a tandem Friedel–Crafts acylation/oxo-Michael addition/elimination strategy.

Synthesis of 3‐Substituted 2‐Aminochromones via Sn(IV)‐Promoted Annulation of Ynamides with 2‐Methoxyaroyl Chlorides.

Hydrogen peroxide (H2O2) is a green oxidant that has been widely used. The direct synthesis of hydrogen peroxide (DSHP) significant advantages in terms of high atomic economy and environmentally friendly...

Shen Wang

Papers

Synthesis of 3-Substituted 2-Aminochromones via Sn(IV)-Promoted Annulation of Ynamides with 2-Methoxyaroyl Chlorides

Synthesis of 3‐Substituted 2‐Aminochromones via Sn(IV)‐Promoted Annulation of Ynamides with 2‐Methoxyaroyl Chlorides.

Progress and Perspectives of Pd-based catalysts for direct synthesis of hydrogen peroxide