Gonyautoxin 3

Du Bois and Mulcahy. JACS, 2008, ASAP. DOI: 10.1021/ja805651g.

One quick inspection, and you know we’re looking at a dinoflagellate neurotoxin, with more guanidine groups and derivatives than you can shake a stick at.  Unlike other large families of natural products with common functionalities, there doesn’t seem to be a universal strategy that (whilst ugly) could synthesise the majority of the family.  This means we get to see a whole variety of strategies towards these targets (and ultimately, the daddy, palau’amine).

Du Bois’ approach starts with the use of L-serine as the starting material, and source of asymmetry.  Smart choice, as in only four steps they had dihydropyrrolo[1,2]pyrimidin-1(2H)-one product shown