Aminium cation-radical catalysed selective hydration of (E)-aryl enynes?

Chemical Communications Pub Date: 2021-06-22 DOI: 10.1039/D1CC02257A

Abstract

The hydration of carbon窶田arbon triple bonds is an important and atom economic synthetic transformation. Herein, we report a mild and selective method for the catalytic Markovnikov hydration of (E)-aryl enynes to the corresponding enones, mediated through the bench-stable aminium salt, tris(4-bromophenyl)ammoniumyl hexachloroantimonate (TBPA). The chemoselective and diastereoselective method proceeds under neutral metal-free conditions, delivering excellent product yields from terminal and internal alkyne units. The synthesis of biologically important (E)-3-styrylisocoumarins, including a formal synthesis of the natural product achlisocoumarin III, demonstrates the utility of this novel transformation.

Graphical abstract: Aminium cation-radical catalysed selective hydration of (E)-aryl enynes
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