Supramolecularly assisted synthesis of chiral tripodal imidazolium compounds

Supramolecular interactions based on amide groups direct the preferential formation of tritopic instead of monotopic or ditopic imidazolium compounds.

Self-catalysis in thermal hysteresis during random-coil to helix-dimer transition of the sulfonamidohelicene tetramer

The sulfonamidohelicene tetramer changes its structure between a random-coil and a helix-dimer, by which molecular thermal hysteresis appears.

Uncovering the selection criteria for the emergence of multi-building-block replicators from dynamic combinatorial libraries

A family of self-replicating macrocycles was developed using dynamic combinatorial chemistry. Replication is driven by self-assembly of the replicators into fibrils and relies critically on mechanically induced fibril fragmentation. Analysis of separate dynamic combinatorial libraries made from one of six peptide-functionalized building blocks of different hydrophobicity revealed two selection criteria that govern the emergence of replicators from these systems. First, the replicators need to have a critical macrocycle size that endows them with sufficient multivalency to enable their self-assembly into fibrils. Second, efficient replication occurs only for library members that are of low abundance in the absence of a replication pathway. This work has led to spontaneous emergence of replicators with unrivalled structural complexity, being built from up to eight identical subunits and reaching a MW of up to 5.6 kDa. The insights obtained in this work provide valuable guidance that should facilitate future discovery of new complex self-replicating molecules. They may also assist in the development of new self-synthesizing materials, where self-assembly drives the synthesis of the very molecules that self-assemble. To illustrate the potential of this concept, the present system enables access to self-assembling materials made from self-synthesizing macrocycles with tunable ring size ranging from trimers to octamers.

When chiral product and catalyst are the same: discovery of asymmetric organoautocatalysis

The process of asymmetric organoautocatalysis appears to be a natural extension to asymmetric organocatalysis, and holds implications for models on the origin of biological homochirality. The discovery of asymmetric organoautocatalysis (i.e. the process in which the chiral product of a purely organic reaction acts as an organocatalyst for its own formation under conservation of its absolute configuration) and more recent reports on related systems are discussed in this review.

Autocatalysis and organocatalysis with synthetic structures

The discovery of ribozymes led to the proposal of an RNA world, where a single type of molecule was supposedly capable of self-replication and chemical catalysis. We show here that both autocatalysis and organocatalysis can be engineered into a synthetic structure. The compound is shown to selectively accelerate its own formation and catalyze either hydrogenation or nucleophilic addition to alpha,beta-unsaturated aldehydes. The observed reactivity indicates that the components of a purported pre-RNA world conceivably include smaller organic molecules.