Total synthesis and biological properties of novel antineoplastic (chloromethyl)furanoindolines: an asymmetric hydroboration mediated synthesis of the alkylation subunits

1,2-Dihydro-1-(chloromethyl)-5-hydroxy-8-methyl-3H-furano[3,2-e]in dole (CFI) as a novel replacement of the cyclopropylpyrroloindoline (CPI) alkylation subunit of CC-1065, U-71184, and U-73975 (adozelesin) has been synthesized and incorporated into a series of efficacious antineoplastic agents. A partial solution to an asymmetric synthesis of the CFI alkylation subunit has been achieved by the implementation of an asymmetric hydroboration reaction of an intermediate 3-methyleneindoline (13). Extension to the asymmetric synthesis of the CBI and CI alkylation subunits is presented. The demonstration and comparative study of the sequence-selective DNA alkylation properties of the CFI-based agents are detailed, and the preliminary in vitro and in vivo antineoplastic properties of these agents in the human epidermoid cell lung carcinoma (T222) are described.