Total Synthesis of Ningalin C

摘要

Ningalin C is a highly colored pyrrole alkaloid isolated from an unidentified Western Australian ascidian of the genus Didemnum by Fenical et ah, together with biogeneti-cally related congeners, ningalins A, B, and D, all of which are derived from 3,4-dihydroxyphenylalanine in biosyn-thetic pathway.1 Structurally, it is composed of a densely substituted benzo[e]indole-2,5(3H)-dione core, two o-catechol subunits and 3,4-dihydroxyphenethyl chain on the pyrrole nitrogen (Figure 1).