Reversible Thiazolidine Exchange: A New Reaction Suitable for Dynamic Combinatorial Chemistry

New dynamic combinatorial libraries (DCLs) were generated using the reversible aminothiol exchange reaction of thiazolidines and aromatic aldehydes. The reaction proceeded in aqueous buffered media at pH 4 and room temperature to generate thermodynamically controlled mixtures of heterocycles. The synthesis of an enantiomerically pure thiazolidinyloxazolidine is also reported. The oxazolidine moiety could be exchanged in CH2Cl2 in the presence of catalytic p-TsOH.