Totalsynthese von Camptothecin

The pentacyclic alkaloid camptothecin exhibits pronounced cytotoxicity. Within the framework of structure-property-relationship studies irinotecan (camptosar®) and topotecan (hycamtin®) as camptothecin analogues could be produced and are used in cancer therapy. Regarding easy accessibility of these analogues by synthetic methods an efficient and industrially applicable total synthesis of camptothecin is important. Since so far published total syntheses require a great many reaction steps, it is desirable to develop a new access to camptothecin with overall high efficiency.In this work a novel total synthesis of camptothecin is described. For this a domino Knoevenagel hetero Diels-Alder reaction was employed for constructing the indolizinoquinoline fragment.