Tandem reactions in organic synthesis

Abstract

<p>Chapter One introduces the direct synthesis of 5-substituted naphthoquinones and provides extensive information about peri-metalation on naphthalene derivatives. We successfully developed the methodology for the preparation of 5-substituted naphthoquinones in a concise manner. Synthetically valuable 5-substituted naphthoquinones could be prepared in 4 steps from a commercially available starting material. This new synthetic method was applied to a biologically active perylene analog and could be explored to access other naphthoquinone-containing natural products.;Two and Three describe a new synthetic strategy to construct bridged complex molecules using Diels-Alder/Radical Cyclization (DARC). We successfully developed a new strategy to construct the bridged tricyclic systems via tandem Diels-Alder/radical cyclization process. During this tandem process, we observed the unusual preference for 6-endo-trig over 5-exo -trig in the radical cyclization step. In our effort to expand this strategy to other molecules, we found a concise preparation of alpha-methylene cyclohexenones, which would be useful to construct spirocyclic systems. This new strategy could be applied in the synthesis of the cumbiasin A skeleton and other biologically active natural products in a highly efficient manner.</p>