10.1246/cl.131179
The study presents the total synthesis of (-)-cyclogalgravin and its dicarboxyl analog, utilizing key steps such as the SmI2-promoted Reformatsky type reaction and Sc(OTf)3-mediated highly diastereoselective ring expansion. The synthesis involved various chemicals, including 1-aryl-1,2-dihydronaphthalene analogs, which are of interest due to their natural occurrence and biological activities. Key chemicals used in the synthesis process include dichlorocyclopropane, methyl 1-chlorocyclopropanecarboxylate, and 3,4-dimethoxyphenyl aldehyde, which were transformed through a series of reactions to yield the target compounds. The study also employed reagents like n-BuLi, ClCO2Me, t-BuLi, CO2, K2CO3, MeI, SmI2, HMPA, and Sc(OTf)3 for specific reactions such as methoxycarbonylation, carboxylation, and ring expansion. The purpose of these chemicals was to facilitate the formation of the desired dihydronaphthalene structures with high stereoselectivity, ultimately leading to the efficient synthesis of (-)-cyclogalgravin and its dicarboxyl analog, which have potential applications in医药领域 due to their biological activities.
10.1021/ja063421a
This study presents a novel approach to the Nazarov reaction, emphasizing the generation of pentadienyl cations through sequential electrocyclic ring opening and closure. The research explores the use of alkenyl-substituted dihalocyclopropanes as precursors, employing conditions such as thermal treatment and silver(I) salts (e.g., AgBF4) to induce reactions. The key chemicals used include dichlorocyclopropanes, 2-triisopropylsilyloxydienes, and silyl ethers. Various substituted cyclopropanes were synthesized and subjected to conditions leading to cyclopentenone products, including regioselective and diastereoselective outcomes. The findings highlight the potential of this method to complement traditional Nazarov intermediates, offering pathways for novel products.
