Nickel-catalyzed reductive defunctionalization of esters in the absence of an external reductant: activation of C-O bonds.

The nickel-catalyzed reductive cleavage of esters in the absence of an external reductant, which involves the cleavage of an inert acyl C-O bond in O-alkyl esters is reported. Various groups, such as N-containing heterocycles, esters, amides, and even arene rings can function as a directing group.