Pd(II)/Zn co-catalyzed chemo-selective hydrogenation of α-methylene-γ-keto carboxylic acids

An efficient Pd/Zn co-catalyzed chemo-selective hydrogenation of α-methylene-γ-keto carboxylic acids is described. This methodology offers a divergent synthesis of α-methyl-γ-keto carboxylic acids, α-methylcarboxylic acids, and lactones starting from α-methylene-γ-keto carboxylic acids via selective hydrogenation by varying the catalytic conditions avoiding the use of high pressure of hydrogen. The reaction also showed broad substrate tolerance to give the desired products in good to excellent yields.