“Chemists prepare (-)-Crinipellin A”
In a pursuit known as “total synthesis,” an organic chemist will replicate a complicated molecule found in Nature in the synthetic chemical laboratory, step by step. Very recently, the laboratory of Hee-Yoon Lee in the Department of Chemistry at KAIST has artificially prepared, for the first time Crinipellin A. A so-called “tandem 2 + 3 cycloaddition” was used in the efficient reaction in which a chain-like molecule is brought together into several rings, sometimes in a single synthetic step. This important reaction has been developed and optimized by the Lee laboratory over the past few years.
The essential joy of studying the Natural Sciences is to be able to fully appreciate what nature has provided.Scientists commonly mimic aspects of the natural world. From a chemist’s point of view, to construct a natural molecule precisely by artificial means by efforts in the laboratory, not the way nature does it (biosynthetically),continues to be a highly sought-after undertaking which is a virtual “art form” that drives the pharmaceutical industry. In a pursuit known as “total synthesis,” an organic chemist will thus replicate a complicated molecule found in nature in the synthetic chemical laboratory, step by step. Of the various kinds of molecules targeted over the years, there are various target species that hold numerous challenges based on the extent of stereogenic centers (places where chirality or “handedness” emerges) and distinct functionalization as well as carbon backbone characteristics exist. Another factor is the number and “size” of the steps required to effect the completion of the molecule.
Recently, the laboratory of Hee-Yoon Lee has prepared, for the first time, anelegant and efficient synthesis of Crinipellin A. Crinipellens are natural components of fungi which were first isolated in 1979.A molecular structural study was reported in 1985, but this structure was of a closely related compound (Crinipellin B). The synthesis of Crinipellin A involves a reaction known as a “tandem 2 + 3 cycloaddition” – this is in fact a very efficient method of preparation. In the reaction, a chain-like molecule is brought together into several rings, sometimes in a single synthetic step. This kind of chemistry has been developed over the years by the Lee laboratory: the methodology previous used to form triquinanes (three rings) from a linear and acyclic starting material can now be extended to larger networks. This has led to the present paper which involves a cyclopentane precursor that then goes on to form tetraquinane (four rings). It is vital to underscore this fine art of such intricate and complete and structure synthesis in the age of nanoparticle research.
“Total Synthesis of (-)-Crinipellin A” Kang, Taek; Song, Seog Boem; Kim, Won-Yeob; Kim, Byung Gyu; Lee, Hee-Yoon , Journal of the American Chemical Society (2014), 136(29), 10274-10276.
NOTE: The research group of Lee has also authored recently, “Total Synthesis of Panaginsene with Structural Revision“ authored by Geum, Sujeong; Lee, Hee-Yoon Organic Letters 2014, 16(9), 2466-2469