Synthetic Applications of the BHQ Reaction: Towards the Total Synthesis of Plumbagin

by Michael Mun Wong

Institution: University of Manchester
Year: 2015
Keywords: plumbagin, plumbagin synthesis, ATRC, BHQ
Record ID: 1406244
Full text PDF: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:261671


Plumbagin is a naturally occurring quinone which is well documented for having a plethora of beneficial medicinal properties. This report explores a synthetic preparation of the natural product through the use of the BHQ reaction, a unique and efficient benzannulation method which regiospecifically installs a halogen on the 4-position on the newly formed six-membered ring, during the course of a ten-step total synthesis.The synthetic route commences with 2-methyl hydroquinone and after subjugation to several chemical transformations 5-chloro-1,4-dimethoxy-2-methyl naphthalene was afforded supported by evidence from X-ray crystal diffraction analysis. Although the installed aryl chloride proved unsuitable for further chemical manipulation an alternative substrate, an aryl bromide, was produced and successfully displaced with a boronic ester providing a suitable functional precursor leading to the target compound however further attempts to isolate plumbagin from the by-products in the last step did not come to fruition.