The possibility of combining the electronic properties of oligothiophenes with potential chiroptical properties has fueled research in the area of thiaheterohelicenes. Recent reports that these molecules also exhibit fascinating interactions with biologically important macromolecules place further emphasis on the need for new synthetic methods to access thiaheterohelicenes. This review highlights the synthetic methods currently being used to prepare thiaheterohelicenes and discusses the role that chemical synthesis plays in the exploration of the properties of these helically chiral molecules.

Enzymes lock in planar chirality: Molecules with very large rings—macrocycles—are often conformationally constrained, and some exhibit planar chirality when substituents of the ring cannot rotate freely. Restricted rotation is generally valued in macrocycles because it can hold the molecule in functional conformations. Using a well-established lipase enzyme, Gagnon et al. developed a synthesis of planar chiral macrocycles with handles that can be easily functionalized. Computational docking suggests how using an enzyme as the catalyst for sequential acylation reactions can impart the observed stereochemistry. Science , this issue p. 917