A novel general protocol for the construction of hydantoins and thiohy
dantoins on a solid support has been developed. Using this novel metho
dology, the synthesis of a diverse 96-compound library has been achiev
ed. Resin-bound dipeptides are cyclised via the formation of an interm
ediate isocyanate or isothiocyanate on resin as the key step in the st
rategy.