Substituted Butenylindium Generated by Transmetalation of Cyclopropylmethylstannane with Indium Iodide: Synthesis and Characterization of Monobutenylindium

Transmetalation between substituted cyclopropylmethylstannanes and indium iodide provided the corresponding mono- and dibutenylindium species. The bulky substituent on a cyclopropyl ring selectively afforded the monobutenylindium species, which allowed the isolation and X-ray structural analysis of the monobutenylindium complex. In an investigation of the generated substituted butenylindium species, we found that indium halide interacted with the less sterically hindered carbon−carbon bond of the cyclopropyl ring during transmetalation. In addition, we examined the radical coupling reactions of substituted butenylindium species with an α-iodoester. The distribution of the cyclopropylmethylated and alkene products was evidence that the reactions were remarkably affected by the steric effect of the substituents of the butenylindium species, which retarded the cyclization of the radical intermediate.