Organocatalytic, Highly Enantioselective Vinylogous Mukaiyama–Michael Reaction of Acyclic Dienol Silyl Ethers

Now also acyclic: The first catalytic, enantioselective, vinylogous Michael reaction of linear, acyclic dienol silyl ethers was achieved. The reaction, based upon the principle of iminium ion catalysis, delivered 1,7-dioxo compounds in one step with good yields, complete regio-, and excellent enantioselectivity. γ-Substituted dienol silyl ethers furnished products with two new stereogenic centers with good diastereoselectivity. Ms = mesityl, PNBA = para-nitrobenzoic acid.