Total Synthesis of Cyrneine A

The tricyclic diterpene cyrneine A featuring a hexatrienal unit was prepared synthetically for the first time by a Heck reaction, a carbene ring expansion, and a reductive carbonylation. The structure of the natural product was assigned by X‐ray crystal analysis of a synthetic sample

Synthesis of 2‑Thiocarbohydrates and Their Binding to Concanavalin A

A convenient and general synthesis of 2-thiocarbohydrates via cerium ammonium nitrate oxidation of the thiocyanate ion is described. Radical addition to glycals proceeds with excellent regio- and good stereoselectivities in only one step, deprotection affords water-soluble 2-thio saccharides. Binding studies to Con A have been performed by isothermal titration calorimetry (ITC) and saturation transfer difference (STD) NMR spectroscopy. The 2-thiomannose derivative binds even stronger to Con A than the natural substrate, offering opportunities for new lectin or enzyme inhibitors