GaCl₃-Catalyzed Stereoselective Synthesis of E-α,β-Unsaturated Ketones

Significance

The authors have developed a very mild and highly stereoselective synthesis of α,β-unsaturated ketones. Gallium chloride was the new catalyst used for this reaction in 10 mol% loading. GaCl₃ has a very unusual reactivity, and a variety of new reactions have been reported recently (for a short review see: R. Amemiya, M. Yamaguchi, Eur. J. Org. Chem. 2005, 5145-5150). A variety of aryl substrates added to ynones giving the products in high yield and selectivity. All reactions are finished in less than one hour and yields are generally very high.