Quantum chemical computations performed by Young Hong of the Tantillo group on reactions occuring in the biosynthesis of complex terpene natural products were recently described in two important papers, one in Nature Chemistry (2009, 1, 384) and the other in the Journal of the American Chemical Society (2009, 131, 7999). The former was also highlighted in a recent issue of Nature Chemical Biology (2009, 5, 614).

These papers point to a variety of general principles that govern the mechanisms of complex carbocation rearrangements occuring in terpene biosynthesis. The importance of several of these principles has been underestimated before or, in some cases, has been overlooked entirely. Of particular note is the proposal that bifurcating pathways on potential energy surfaces, which have received considerable interest in recent years in non-biological contexts, may actually be relevant to biosynthesis. A bifurcating pathway is one in that splits after a transition state structure is reached, allowing a single transition state structure to be connected directly to two products. Interestingly, one branch of the pathway examined by Young leads to a known natural product, while the other leads to a complex molecular architecture that has never been observed in a natural product.


For additional information, see:

http://blueline.ucdavis.edu/2ndTier/3rdTier/TerpBiosynth.html