Date: 2009. 7. 9, 5:00 PM Place: Mogam Hall, Bldg 500 -Abstract- Ryanodine (1) is a potent modulator of calcium release channel that is known as the ryanodine receptor. It alters the function of the receptor in a complex manner: submicromolar concentrations lock the channel in a long-lived open state, whereas micromolar or greater concentrations inhibit Ca2+ release. From a synthetic point of view, the complex molecular architecture of 1, which includes five rings, eleven stereogenic centers, seven oxygenated carbons, and seven contiguous fully substituted carbons, is a daunting challenge for chemical synthesis. From our perspective, ryanodine 1 and related structures present an ideal platform to devise efficient strategies for building highly oxygenated multi-cyclic carboskeleton. In addition, development of a flexible synthetic scheme to 1 would enable generation of chemical derivatives with distinct functional properties toward the ryanodine receptors. As an initial phase of this study, we report a concise route to highly substituted skeletons of the ABDE-tetracycle by taking advantage of its embedded symmetric structure.