Zinc Bromide, typ. 30 % solution in THF
The use of a 'ready-made' THF solution avoids the handling of the very hygroscopic and dusty ZnBr2 powder.
The ZnBr2 THF solution was developed mainly for the application in organic synthesis, e.g.:
- transmetallation of organomagnesium and organolithium compounds to the corresponding zinc reagents for C-C coupling reactions (Negishi protocol).
- formation of zinc enolates by deprotonation of carbonyl compounds using standard bases followed by transmetallation with ZnBr2.
- catalysis of cycloaddition reactions e.g. Diels-Alder reactions of electron rich dienes with carbonyl compounds.
- preparation of selective reducing agents, e.g. Zn(BH4)2 by reaction of NaBH4 with ZnBr2.
McGarvey, G.J. in Encyclopedia of Reagents for Organic Synthesis, Paquette, L.A., Ed. John Wiley and Sons, New York (1995), Vol. 8, 5544.