Spotlights on Recent JACS Publications

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Spotlights pubs.acs.org/JACS

Spotlights on Recent JACS Publications

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INSIDE LOOK AT A TERPENE CYCLIZATION CATALYST Terpenes represent one of the largest classes of natural products, valued for their diverse biological activity and utility in treatment of human diseases. However, challenges in controlling the selectivity of terpene cyclization reactions have made large-scale production of these compounds challenging. Nature is much more efficient, as enzymes can selectively promote tail-to-head (THT) terpene cyclizations within a defined pocket. Recently, a group of researchers led by Konrad Tiefenbacher have developed the first successful THT terpene cyclization inside a synthetic catalyst (Nature Chemistry, DOI: 10.1038/nchem.2181). The cavity within the supramolecular hydrogen-bond-based capsule mimics an enzyme pocket, providing a defined chemical environment for the substrate to bind and cyclize in a selective fashion. Now the researchers have elucidated the substrate scope and mechanistic details concerning this discovery (DOI: 10.1021/ jacs.7b04480). The authors demonstrate that noncovalent interactions between the enzyme-like capsule and leaving group of the substrate directly influence product selectivity. Moreover, a series of kinetic studies reveal the synergistic role between the capsule and trace acid in promoting catalytic activity. The fundamental insights gained from these studies will aid in the development of artificial catalysts capable of promoting transformations that were once only possible with natural enzymes. Nicole Camasso, Ph.D.

METAL-FREE OR NOT METAL-FREE, THAT IS THE QUESTION High-turnover catalysis (HTC) is a powerful method in organic synthesis that achieves high-yielding product formation with very small catalyst loadings (