Bismuth chloride mediated allylation of carbonyl compounds in aqueous media: a mechanistic investigation

The bismuth chloride mediated, aluminum promoted aqueous Barbier type coupling of allyl unit with carbonyl compounds which gives the corresponding homoallyl alcohol is studied. The transient in situ generated allylbismuth(III) bromide intermediate was studied by 1H NMR and GCMS for mechanistic study of allylation. The role of solvent, temperature, and additives in their formation is also studied. The results show that the most reactive intermediate species is CH2CHCH2BiBr2 which mediates allylation of aldehydes and ketones with different substituents with good yields.