Alkene-Assisted Nickel-Catalyzed Regioselective 1,4-Addition of Organoboronic Acid to Dienones: A Direct Route to All-Carbon Quaternary Centers

Abstract

A nickel-catalyzed highly regioselective 1,4-addition reaction of boronic acids to dienones to form products with an all-carbon quaternary center is described. The 3-alkenyl group of dienones is the key for the reaction to proceed smoothly. A mechanism involving the coordination of the dienyl group to the nickel center is proposed.

Ni(II)-catalyzed asymmetric alkenylations of ketimines

“…Addition of organometallic reagents to electron-deficient double bonds is one of the most powerful reactions for the construction of various molecular skeletons. To expand the viability of transition-metal catalysts for use in addition reactions of organoboron reagents and to lower the cost of transition-metal catalysts for use in industrial processes, the first-row late transition-metal-catalyzed addition of organoboron reagents to double bonds has become an attractive target 6 – 24 . Nickel, as a first-row transition-metal in the same group as that of palladium, has attracted much attention 25 , 26 .…”

“…Nickel, as a first-row transition-metal in the same group as that of palladium, has attracted much attention 25 , 26 . However, nickel-catalyzed additions of organoboron reagents to electron-deficient double bonds have not been widely reported 14 – 24 .…”

Nickel-Catalyzed Transformation of Alkene-Tethered Oxime Ethers to Nitriles by a Traceless Directing Group Strategy

“…As a result, the reaction of these substrates yielded 2a in low yield (Scheme , eq 2). These results indicated that the alkene group tethered to an oxygen atom on the oxime via the one methylene unit is essential to proceed the directed transformation. , Additionally, we also carried out the transformation of secondary oxime ether 7 under the same reaction conditions (Scheme , eq 3). GC analysis of the reaction mixture showed that 2a , 1-phenyl-2-propen-1-ol, and propiophenone were formed in 98%, 82%, and 1% GC yield, respectively.…”