Organoastatine chemistry. Astatination via electrophilic destannylation

Substantial interest is currently focused on the α-emitting radiohalogen 211At, principally because of its potential use in the radiation therapy of cancer. Knowledge of organoastatine chemistry is incomplete and existing methods for its incorporation restrict the range of compound which may be labeled. Aryl and vinyl Sn(IV) compounds are notably susceptible to substitution of tin by a variety of electrophiles. We have investigated the reaction of aryltrialkylstannanes with astatine and report here the first examples of astatodestannylation. Formation of aryl astatides proceeds rapidly, cleanly and under mild conditions. The data further elucidate aspects of astatine reactivity and suggest a general route to synthesize astatinated compounds. (author)