Unprecedented chemical structure and biomimetic synthesis of erucalexin, a phytoalexin from the wild crucifer Erucastrum gallicum

The isolation, structure determination, total synthesis and antifungal activity of erucalexin, a novel phytoalexin produced by the wild crucifer dog mustard are described. Erucalexin is a structurally unique plant alkaloid, representing the first example of a spiro[2H-indole-2,5′(4′H)-thiazol]-3-one, likely derived from a C-3–C-2 carbon migration in a 3-substituted indolyl nucleus.