Total synthesis of asperlicin C, circumdatin F, demethylbenzomalvin A, demethoxycircumdatin H, sclerotigenin, and other fused quinazolinones

Using scandium triflate and microwaves, the direct double dehydrocyclization of anthranilate-containing tripeptides was achieved, affording the total syntheses of (i) quinazolino[3,2-a]benzodiazepinediones (), (ii) diazepino[2,1-b]quinazolinediones (), and (iii) pyrazino[2,1-b]quinazolinediones () with good overall isolated yields (23-43%, 37-47% and 31-56%, respectively). Among the quinazolino[3,2-a]benzodiazepinediones synthesized, (sclerotigenin), (circumdatin F), and (asperlicin C) are natural products.