摘要:
A practical, total synthesis of seco-(+)-oxaduocarmycin 3a, an analogue of the highly cytotoxic natural product, duocarmycin SA (1), is described. The 13-step synthesis features a novel and efficient intramolecular aryl radical cyclization onto a vinyl chloride as a direct entry to the (chloromethyl)indoline alkylating subunit 14. Subsequent resolution, utilizing a preparative Chiralpak AD column, provided enantiomerically pure alkylating subunits 14a and 14b which were elaborated to seco-(+) and ent-(-)-oxaduocarmycins, 3a and 3b, respectively. The natural enantiomer 3a was active at pM concentrations and exhibited 7-50-fold higher potentcy than its enantiomer 3b in in vitro cytotoxicity assays.