On the role of additives in alkyl-alkyl Negishi cross-couplings.
An additives study for the alkyl-alkyl Negishi reaction using an NHC-Pd catalyst revealed that bromide salts promote coupling while the cation is mechanistically benign. A double titration revealed that the cross-coupling begins at a 1 : 1 ratio of LiBr : (n)BuZnBr, suggesting that a higher-order zincate, presumably Li(m)Zn((n)Bu)Br(3)((2-m)-), is the active transmetalating agent.
Achonduh
George T
GT
Department of Chemistry, York University, 4700 Keele Street, Toronto, Ontario, M3J 1P3, Canada.
Hadei
Niloufar
N
Valente
Cory
C
Avola
Stephanie
S
O'Brien
Christopher J
CJ
Organ
Michael G
MG