EFFICIENT SYNTHESIS OF BIOACTIVE NATURAL PRODUCTS EMPLOYING CATALYTIC CASCADE REACTIONS.

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Recently, the development of catalytic cascade reactions has attracted considerable attention because cascade reactions are environmentally friendly and economical. In this research, the author has examined tin-free cascade homoallyl-homoallyl radical rearrangement process and Ni-catalyzed cascade electroreductive cyclization protocol.(1)Total Synthesis of Serofendic Acids A and B Employing Tin-Free Cascade Homoallyl-Homoallyl Radical RearrangementSerofendic acids A and B are neuroprotective agents that were isolated from fetal calf serum in 2002. The unique structures were shown to consist of bicyclo[2.2.2]octane ring system bearing an unusual sulfoxide side chain. The serofendic acids are attractive targets for total synthesis, not only due to their neuroprotective activity, but also because of the challenge of their structures, which feature nine stereocenters and atisane framework. In this research, a total synthesis of both (-)-serofendic acids A and B has been accomplished. The s … More ynthetic strategy involved the use of a tin-free cascade homoallyl-homoallyl radical rearrangement for the construction of bicyclo[2.2.2]octane ring system. The methodology developed here should provide access to synthetic analogues of serofendic acids.(2)One-Pot Assembly of Tricyclo[6.2.1.0^<1,6>]undecane-4-one and Related Polycyclic Compounds by Cascade Electroreductive CyclizationThe assembly of polycyclic molecules through carbon-carbon bond-forming processes in a single operation is a significant direction for organic synthesis. Therefore, various types of cascade reactions have been actively developed in recent years. In this research, the author has developed a strategy based on intramolecular cascade electroreductive cyclization, and the cascade electroreductive cyclization has been successfully applied to the construction of tricyclo[6.2.1.0^<1,6>]undecane-4-one and related polycyclic compounds. The favorable profile of this novel protocol is increased by the low cost as well as the toxicologically and environmentally benign character of electrochemistry. Less