An insight into copper catalyzed allylation of alkyl zinc halides. Comparison of reactivity profiles for catalytic and stoichiometric alkylzinc-copper reagents

Erdik E., Kocoglu M.

Journal of Organometallic Chemistry, cilt.694, sa.12, ss.1890-1897, 2009 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 694 Sayı: 12
  • Basım Tarihi: 2009
  • Doi Numarası: 10.1016/j.jorganchem.2009.01.026
  • Dergi Adı: Journal of Organometallic Chemistry
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Sayfa Sayıları: ss.1890-1897
  • Anahtar Kelimeler: Allylic coupling, Alkylzinc halides, Reactivity profiles, Kinetics of allylation, Alkylzinc-copper reagents, Catalytic allylation, CROSS-COUPLING REACTIONS, ALLYLIC DERIVATIVES, GRIGNARD-REAGENTS, HIGHER-ORDER, ALPHA-POSITION, ORGANOMETALLICS, CARBOXYLATES, CHLORIDES, REGIOSELECTIVITY, SUBSTITUTION
  • Ankara Üniversitesi Adresli: Evet

Özet

The γ-selective allylation of catalytic and stoichiometric alkylzinc-cuprates have been kinetically studied. The reactivity profiles generated by allylation reactions of n-butylzinc chloride catalyzed by CuX compounds (X = I, Br, Cl, CN, SCN) and also catalyzed by n-butylzinc-copper reagents and di n-butylzinc-copper reagents were evaluated. Reactivity profiles for allylation of stoichiometric n-butylzinc-copper reagents and di n-butylzinc-copper reagents were also prepared. All CuX compounds have been screened for the preparation of Grignard reagent derived n-butylzinc-copper reagents and di n-butylzinc-copper reagents. The evaluation of the profiles indicates that the active catalyst might be RCu(X)ZnCl and also to some degree, R2CuZnCl · ZnClX, which both could favor formation of γ-product. All data supports the reductive elimination of σ-allyl Cu (III) complex formed at vinylic terminal to give γ-allylated product with a quite slow isomerization to σ-allyl Cu (III) complex formed at allylic terminal to give α-allylated product. In the allylation mechanism of zinc cuprates, the role of counter ion, ZnCl+ has been discussed. © 2009 Elsevier B.V. All rights reserved.