Oligomerization of 1,2-ethanedithiol: an expedient approach to oligothiaethylenethioglycols

Reactions of ethylenedithioglycol (ETG) with Na(2)CO(3), K(2)CO(3), and Cs(2)CO(3) provided the oligothiaethylenethioglycols (nETG): di- (DETG), tri- (TrETG), tetra- (TETG), and pentathiaethylenethioglycol (PETG), along with higher polymers. The most efficient carbonate was K(2)CO(3) and reactions using DETG and TrETG as starting materials--or their mixtures--were also found to afford similar species. This largely unknown oligomerization process was thoroughly explored and potential pathways were put forward. A convenient conversion of ETG to laboratory quantities of the otherwise scarce and/or expensive DETG, TrETG, TETG, and PETG oligomers, in organic or aqueous media was achieved. Notably, this straightforward reaction takes place without the addition of expensive or toxic metal catalysts and with pure water as the solvent, thereby highlighting its potential as a green chemical reaction. Moreover, the process opens up new approaches to dynamic combinatorial libraries (DCLs) of oligomers and macrocycles with manifolded nETG [(SCH(2)CH(2))(n)S] bridges.