We herein report our first results on the use of simple acetalation chemistry in the service of dynamic combinatorial libraries (DCLs); the reaction between triethylene glycol and 4-nitrobenzaldehyde afforded a DCL of more than 15 cyclic and acyclic species; all of which were separated and characterized; the smaller macrocyclic compounds were successfully amplified by the use of ammonium ions.

No abstract

Beta substituted thiols and various derivatives containing the HX-C-C-SH motif oligomerise in water, preferably in the presence of a carbonate salt. The reaction yields oligomers consisting of one thiol end group, a thiaethylene backbone and an additional terminal group corresponding to the starting material used.Mechanistic studies, as well as the scope of substrates and products of these new promising condensation processes, are presented. In addition, strong nucleophiles were also reacted with mercaptoethanol under simple reaction conditions, leading to the selective formation of more complex molecules.

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.

We present a unique class of polythiacrown macro-and gigantocyclic [9] systems, consisting of ethylene 1,2-dithioglycol (ETG) to poly(ethylene thioglycol) (ETG n ) bridges over one to six diacetal units of the cis-1, 3,5, type. The latter is a dissymmetric, chiral moiety, incorporating a cavity with built-in high electron lone pair concentration, serving as the "core" of chiral macrocyclic host systems with good inclusion ability of ions and polar molecules. We describe two approaches: (i) the reactions of the 2,6-bis(bromomethyl)-cis-TOD podand (6) with ETG or higher ETG n s (12 n ), in Cs 2 CO 3 promoted processes, leading to the innate but uncontrolled formation of polythiacrown-TOD macrocycles having ETG/TOD ratios of 1:1 (7), 2:2 (8) and further 3:3-6:6 (11 1/m ) [10] macrocycles via open dithiol intermediates, and (ii) judicious preparation, using K 2 CO 3 , of oligomeric dibromide intermediates with ETG n :TOD ratios 1:2, 2:3 or 3:4