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.