Barbier-type allylation of aldehydes with allylic bromide and tin(II) chloride in presence of potassium iodide and ammonium chloride in water.
During the reaction tin(II) iodide forms what is visible from the color change of the reaction. Tin(II) iodide is a bight orange salt that is not really soluble in water in the presence of ammonium ions.
The Barbier reaction is an organometallic reaction between an alkyl halide (chloride, bromide, iodide), a carbonyl group and a metal. The reaction can be performed using magnesium, aluminium, zinc, indium, tin, samarium, barium or their salts. The reaction product is a primary, secondary or tertiary alcohol. The reaction is similar to the Grignard reaction but the crucial difference is that the organometallic species in the Barbier reaction is generated in situ, whereas a Grignard reagent is prepared separately before addition of the carbonyl compound.
The Barbier reaction is named after Victor Grignard's teacher Philippe Barbier.
