diastereoselective. The allylation of benzaldehyde by 1-chlorobut-2-ene in 1,3-dimethylimidazolidin-2-one (DMI) does not occur with tin(II) chloride or bromide but does proceed with tin(II) iodide and exhibits gamma-syn selectivity which is unusual for a Barbier-type carbonylallylation. In the carbonylallylation by 1-chlorobut-2-ene with any tin(II) halide, the addition of tetrabutylammoniumiodide (TBAI) accelerates