Reactivity of mixed organozinc and mixed organocopper reagents: 14. Phosphine-nickel catalyzed aryl-allyl coupling of (n-butyl)(aryl)zincs. Ligand and substrate control on the group selectivity and regioselectivity

KALKAN M., Erdik E.

JOURNAL OF ORGANOMETALLIC CHEMISTRY, cilt.818, ss.28-36, 2016 (SCI-Expanded, Scopus)

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 818
  • Basım Tarihi: 2016
  • Doi Numarası: 10.1016/j.jorganchem.2016.05.014
  • Dergi Adı: JOURNAL OF ORGANOMETALLIC CHEMISTRY
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Sayfa Sayıları: ss.28-36
  • Anahtar Kelimeler: (Alkyl)(aryl)zincs, Mixed diorganozincs, Allylation, Ni catalyst, Regioselectivity, Group selectivity, CONJUGATE MICHAEL-ADDITIONS, GRIGNARD-REAGENTS, DIORGANOZINC COMPOUNDS, ASYMMETRIC-SYNTHESIS, ALKYL GRIGNARD, SECONDARY, ALCOHOLS, METHYL, CHEMISTRY, ARYLATION
  • Ankara Üniversitesi Adresli: Evet

Özet

The group selectivity and regioselectivity in the allylation of mixed (n-butyl)(aryl) zinc reagents in THF depends on the nickel catalyst type and also on nature of the allylic substrate. Allylation of (n-butyl)(phenyl) zinc reagent with alkyl substituted primary allylic chlorides and acetates in the presence of NiCl2(dppf) catalysis affords the phenyl coupling product with gamma-selectivity. However, allylation with aryl substituted primary allylic substrates results in both phenyl-and alkyl-coupling products with medium alpha-selectivity in the presence of NiCl2(dppf) catalysis whereas phenyl coupling product is formed with alpha-selectivity in the presence of NiCl2(Ph3P)(2) catalysis. This new NiCl2(dppf) catalyzed protocol for gamma-selective aryl allylation of (n-butyl)(aryl) zinc reagents with alkyl substituted primary allylic chlorides in THF at room temperature provides an atom economic alternative to allylation of (aryl)(2)Zn reagents. A mechanism for the dependence of group selectivity and regioselectivity of Ni catalyzed allylation of (n-butyl)(aryl)zinc reagents on the catalyst ligand and the substrate was proposed. (C) 2016 Elsevier B.V. All rights reserved.