Silver-catalysed reactions of alkynes: recent advances
Silver is a less expensive noble metal. Superior alkynophilicity due to π-coordination with the carbon–carbon triple bond makes silver salts ideal catalysts for alkyne-based organic reactions. This review highlights the progress in alkyne chemistry via silver catalysis primarily over the past five years (ca. 2010–2014). The discussion is developed in terms of the bond type formed with the acetylenic carbon (i.e., C–C, C–N, C–O, C–Halo, C–P and C–B). Compared with other coinage metals such as Au and Cu, silver catalysis is frequently observed to be unique. This critical review clearly indicates that silver catalysis provides a significant impetus to the rapid evolution of alkyne-based organic reactions, such as alkynylation, hydrofunctionalization, cycloaddition, cycloisomerization, and cascade reactions.