PMC

Unified Mechanism.

Optimal ligand for different substrate combinations.

A hypothetical reductive conjugate addition mechanism with an allylnickel(II) intermediate (II).

The reductive Heck consensus mechanism and its relationship to the limitations of the methods.

^a Reactions conducted as in . ^b With Ar-Br, 58% yield.

Comparison of three approaches to conjugate addition reactions that highlights the advantages of this study (C).

Reaction of (L10)Ni(cod) with Ph-I ( ), cyclohexenone + Et₃SiCl ( ), Et₃SiCl (●), and cyclohexenone ( ) as monitored by UV-Vis at 450 nm. For full UV-Vis spectra and expanded plots of all four reactions, see .

^a Reactions conducted as in . ^b With Ar-Br, 44% yield. ^c Yield based on a single run.

Reaction of (L1)Ni(cod) with 2-bromoheptane ( ), cyclohexenone + Et₃SiCl ( ), Et₃SiCl (●), and cyclohexenone ( ) as monitored by UV-Vis at 880 nm. For full UV-Vis spectra and an expanded plot of all four reactions, see .

^a Reactions conducted as in . ^b 1.2 Equiv of aryl iodide was used instead of 1 equiv. ^c Product contaminated with a small amount of hydrodehalogenated arene.

^a See for full details. Yields of stoichiometric reactions are based upon the amount of nickel, yields of catalytic reaction is based upon the amount of 2-bromoheptane. Yields are uncorrected vs. dodecane internal standard.

^a Ratio of enone : Ar-I : R₃Si-Cl : catalyst was 1.0 : 1.0 : 1.1 : 0.01. Yields reported are of isolated, pure material (average of two runs). ^b Reaction temperature was 40 °C. ^c With ligand L2 and after deprotection by KF in methanol. Yield reported is for two steps. ^d Products isolated as mixtures of diastereomers: 6, 1:1; 7, 6:1.