A nickel catalyst for the addition of organoboronate esters to ketones and aldehydes

Article abstract of DOI:10.1021/ol9017613

A Ni(cod)₂/IPr catalyst promotes the intermolecular 1,2-addition of arylboronate esters to unactivated aldehydes and ketones. Dlaryl, alkyl aryl, and dialkyl ketones show good reactivity under mild reaction conditions (<80° C, nonpolar solvents, no strong base or acid additives). A dramatic ligand effect favors either carbonyl addition (IPr) or C-OR cross-coupling (PCy₃) with aryl ether substrates. A Ni(0)/Ni(II) catalytic cycle initiated by the oxidative cyclization of the carbonyl substrate Is proposed.