A nickel-catalyzed α,β-coupling of saturated ketones

Abstract

An investigation of nickel-catalyzed conditions under which an α,β-coupling of saturated ketones occurs is presented. Studies of reaction conditions reveal that the coupling occurs to produce 1,5-diketones in up to 82% yield using a Ni/PPh3 catalyst with a slight excess of LiHMDS base in the presence of 1-bromo-2-methyl-1-propene at 22°C. This reaction occurs mainly with alkyl aryl ketones. While the method does not appear to be general or high yielding, an awareness of the conditions under which it occurs is important to investigators studying enolate coupling under similar conditions.