Total Synthesis of the Leucetta-Derived Alkaloid Calcaridine A

A biomimetically guided total synthesis of the Leucetta-derived aminoimidazole alkaloid, calcaridine A, is described. The synthesis relies on position selective metalations of a 4,5-diiodoimidazole derivative to provide a tetrasubstituted imidazole. Subjection of this polysubstituted imidazole derivative to oxidative rearrangement with a Davis oxaziridine provides the corresponding imidazolone core of calcaridine A.