A short synthesis of de-‘prenyl’-ardeemin

A four-step synthesis of the ardeemin framework by starting from N-2-aminobenzoyl-α-amino esters is described. In the last step, the acid promoted cyclization of the 1,4-anti-4-alkyl-1-(3-indolylmethyl)-2,4-dihydro-1H-pyrazino2,1-b]quinazoline-3,6-diones occurs irreversible and stereocontrolled.