Evolution of a Synthetic Strategy for the Variecolortides

The variecolortides are a family of unusual natural products that combine motifs from a variety of biosynthetic streams. Herein, we present the gradual evolution of a convergent synthetic strategy that ultimately culminated in a reaction cascade featuring a hydrogen shift and a cycloaddition followed by a spontaneous air oxidation. Attempts to link an anthrone building block with an exo-methylene diketopiperazine using radical chemistry were ultimately unsuccessful, but led to interesting observations that shaped our successful strategy. The total synthesis of variecolortide C is presented for the first time.