A new enantioselective approach to the core structure of hypoxia selective prodrugs related to the duocarmycins

The indoline scaffold of hypoxia selective prodrugs of DNA-alkylating agents related to the duocarmycin natural products was synthesized via an enantioselective Friedel-Crafts alkylation. Easily accessible starting materials and good stereoselectivity in the alkylation step provide an enantioselective synthesis of the DNA-alkylating subunit.