The reaction of 2-methylcyclopropylcarbinyltrimethylstannane 1 in chlo
roform with the electrophiles sulphur dioxide, trifluoroacetic acid, a
nd iodine proceeds preferentially with ring cleavage and addition at t
he unsubstituted cyclopropyl methylene. Iodination and acidolysis in m
ethanol proceeds exclusively with tin-methyl bond cleavage.