A single weak-binding event is multiplied into an efficient receptor site for protein surfaces (<10(-1) to >10(6) M(-1) in buffered aqueous solution) in a biomimetic fashion. This has hitherto been done with natural host/guest pairs, but not with artificial receptors. The organic reaction presented is one of very few that enable chemists to fuse multiple ionic building blocks covalently in highly polar solution; this one-pot reaction proceeds with virtually quantitative yield. According to this concept, other building blocks with aldehyde groups can likewise be multiplied into monodisperse functional dendrimers. Small basic proteins are bound by octameric dendrimers in 1:1 or 1:2 complexes with millimolar to submicromolar affinities. The complexation event is studied independently in buffered aqueous solution by three different spectroscopic methods (PFG-LED, UV/Vis, and fluorescence). Potential new applications include recombinant protein purification through Arg tags on immobilized dendrimers and on/off switching of protein function by reversible active-site capping of enzymes.

CycloSal‐nucleosyl‐phosphate triesters are a known class of highly effective nucleotide prodrugs (pronucleotides) of antivirally active nucleoside analogues. Until recently, the synthesis of these compounds always gave diastereoisomeric mixtures. Then, a convergent route for the stereospecific synthesis of cycloSal‐triesters was described to give isomerically pure cycloSal‐prodrugs for the treatment of viral diseases. Here, the development of a stereoselective synthesis of these pronucleotides using various chiral auxiliaries is described. In contrast to pyrrolidine‐ or pyrrolidinone derivatives it was found that a thiazolidine derived from valinol fulfilled all three requirements to act as a suitable chiral moiety, allowing: (i) strong chirality transfer, (ii) the formation of separable diastereoisomeric intermediates, and (iii) a suitable leaving group that allows the introduction of the nucleoside analogue (e.g., d4T) in the final step under mild reaction conditions. The title compounds were obtained with very high diastereoisomeric excesses of more than 95 %.