A Stereoselective Approach to γ-functionalized Carbonyls Exploiting the Cu-promoted S(N)2' Reaction

While several efficient processes exist to effect the stereoselective creation of carbon-carbon bonds in the α- and β-position of carbonyls, functionalization of the γ-position is much more challenging. We disclose an alternative methodology exploiting the Cu-promoted S(N)2' reaction to achieve the addition of various nucleophiles upon the allylic lactones 5a-d which lead to the generation of the desired γ-functionalized α,β-unsaturated aldehydes 6 following in situ hydrolysis.