In this report, a general method for the preparation of 1, 5-dicarbonyl compounds and six membered ring annelation is described. This method involves the reaction of hemiacetal vinylogs 1 with enol ethers 2 or 3 in the presence of a Lewis acid. This reaction was successfully applied to the enol ethers of α and α, α'-hindered ketones such as 2, 2, 6- trimethyl cyclohexanone. α-Cyperone and 6-epi-α-cyperone were obtained using this ...
