Premium
On The Remarkably Different Role of Salt in the Cross‐Coupling of Arylzincs From That Seen With Alkylzincs
Author(s) -
McCann Lucas C.,
Organ Michael G.
Publication year - 2014
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201400459
Subject(s) - negishi coupling , transmetalation , salt (chemistry) , halide , reagent , chemistry , aryl , solvent , zinc , coupling (piping) , inorganic chemistry , combinatorial chemistry , organic chemistry , materials science , alkyl , catalysis , metallurgy
The role of halide salt additives has been investigated in the Negishi reaction involving aryl zinc reagents. Diarylzincs readily transmetallate to Pd in relatively non‐polar media (e.g., THF) with zero salt present and coupling proceeds. Arylzinc halides (ArZnX) fail to couple in THF without salt, but do couple with it. However, unlike alkylzincs that form higher‐order zincates in order to facilitate transmetallation, all that is required with arylzincs in an increase in solvent dielectric as even ZnX 2 works as an additive, which completely terminates alkylzinc coupling.