ORGN 24

The core of teleocidin B4, a fragment of a natural product containing two quaternary stereocenters and a penta substituted benzene ring, was synthesized in four C-C bond forming steps starting from tert-butyl derivative 1. The first step involved alkenylation of the tert-butyl group with a vinyl boronic acid, followed by the annulation of the cyclohexane ring to the benzene nucleus. The third step required a diastereoselective oxidative carbonylation of the geminal dimethyl group, followed by indole assembly via the alkenylation of the phenol nucleus, to afford the teleocidin B4 core. Investigation of the feasibility of the intramolecular alkenylation of the phenol nucleus in the presence of more sensitive functionalities was undertaken. Exploration of the formation of the aryl-nitrogen bond of teleocidin's indolactam ring showed that arylation of L-valine esters with phenyl triflates under Hartwig-Buchwald conditions is possible, yet racemization of L-valine in the course of the reaction was observed.