Synthesis of the Tetracyclic Cores of the Integrastatins, Epicoccolide A and Epicocconigrone A
作者:Joo Young Jeong、Jonathan Sperry、Margaret A. Brimble
DOI:10.1021/acs.joc.9b01796
日期:2019.9.20
6]-tetracyclic core framework that exhibit a broad spectrum of biological activities. A synthesis of the common core of epicoccolide A and epicocconigrone A has been achieved using an umpolung alkylation–lactonization to assemble an isochromanone from which the bridged 1,3-dioxane was readily assembled. A different strategy was required to access the core on the integrastatins; an initial aryllithium addition
methyl and alkoxy substituents at the ortho-positions of the aromatic rings have been measured. The spectra have been assigned with help of the energies, oscillatory strengths, and rotatory strengths of the singlet transitions obtained from DFT calculations. The features of the CD spectra, indicative of the absolute configuration, are the carbonyln–π∗ band and two further strong bands assigned to the