A reductive transmetalation of the pi-allylpalladium(II) complexes, generated in situ from a catalytic amount of a palladium(0) complex and a variety of allylic substrates, with indium(I) salts proceeded smoothly in various solvents, providing a new route for allylindium(III) reagents.

Various gamma-heteroatom-substituted allylindium reagents were prepared, and their reactions with carbonyl compounds were examined. The reaction of 1,3-dibromopropene with metallic indium gave two types of organoindium species, gamma-bromoallylindium and allylic diindium reagents. While the former gave 2-phenyl-3-vinyloxirane upon the coupling with benzaldehyde, the latter gave 1-phenylbut-3-en-1-ol. 1-Iodo-3-bromopropene gave the homoallylic alcohol exclusively. gamma-Alkoxyallylindium reagents were prepared by treating the corresponding gamma-alkoxyallyllithium with indium trichloride and reacted with benzaldehyde to give vic-diol mono ethers in high yields with good syn selectivity. gamma-(Trimethylsilyl)allylindium and alpha,gamma-disubstituted allylindium reagents were also prepared via transmetalation with the corresponding allyllithium.

Diastereoselective couplings of salicylaldehyde, anisaldehyde and 2-pyridylaldehyde with crotyl- and cinnamylindium reagents were studied. The syl/anti selectivity was found to depend largely on the ligands on the indium atom of the allylic indium reagents. A syn-selective cinnamylation of salicylaldehyde was realized by the combination of cinnamyl acetate and indium(I) iodide, whereas an anti-selective coupling with salicylaldehyde was achieved by the indium trichloride/aluminium-mediated cinnamylation.

The Ni-catalysed reaction of triallylindium with internal alkynes underwent bis-allylation to afford octa-1,4,7-trienes in high yield.

No abstract