Reactivity of mixed organozinc and mixed organocopper reagents : 11. Nickel‐catalyzed atom‐economic aryl–allyl coupling of mixed ( n ‐alkyl)(aryl)zincs

Group selectivity in the allylation of mixed ( n ‐butyl)(phenyl)zinc reagent can be controlled by changing reaction parameters. CuCN‐catalyzed allylation in tetrahydrofuran (THF)–hexamethylphosphoric triamide is n ‐butyl selective and also γ‐selective in the presence of MgCl 2 , whereas CuI‐catalyzed allylation in THF in the presence of n ‐Bu 3 P takes place with a n ‐butyl transfer:phenyl transfer ratio of 23:77 and an α:γ transfer ratio of phenyl of 76:24. NiCl 2 (Ph 3 P) 2 ‐catalyzed allylation in the presence of LiCl is phenyl selective with an α:γ ratio of 65:35. The reaction of methyl‐ or n ‐butyl(aryl)zinc reagents with an allylic electrophile in THF at room temperature in the presence of NiCl 2 (Ph 3 P) 2 catalyst and LiCl as an additive provides an atom‐economic alternative to aryl–allyl coupling using diarylzincs. Copyright © 2014 John Wiley & Sons, Ltd.