Chang Ho Oh
Hanyang University, South Korea
Title: Synthetic study to icetexane natural products by using transition-metal catalysis
Biography
Biography: Chang Ho Oh
Abstract
Numerous [m,7,n]-tricyclic structural motifs are found in a variety of icetexane natural products, many of which have a broad spectrum of biological activities. Among various strategies for the construction of seven membered carbocycles, transition metals are utilized as catalysts because of their inherent potential for causing a rapid increase in skeletal complexity. Conjugated Enynals and Enynones serve versatile substrates for the synthesis of such [m,7,n]-tricyclic skeletons via metal catalyzed reactions. They are known to form metal-pyrylium intermediates with alynophilic metals such as Au, Rh, or Pt and the resultant metal-pyrylium intermediates are also known to undergo cycloaddition with an alkene inter and/or intramolecularly (Scheme 1). During the course of our scientific endeavors leading to a general and modular entry to polycyles, we have reported a highly unique behavior of metal-carbene complexes A, formed via [3+2] cycloaddition between metal pyrylium species and a double bond, to polycycles (2-6) depending on the type of substrates, catalysts and reaction conditions.This result have been applied to the total synthesis of icetexanes and abietanes and will be presented in Euro-Chemistry 2019.