Efficient synthesis of achiral seco-cyclopropylbenz[ 2,3-e] indoline analogues:: [4-Amino-2-(5,6,7-trimethoxyindole-2-carboxamido)naphthalen-1-yl]ethyl chloride and [4-hydroxy-2-(5,6,7-trimethoxyindole-2-carboxamido)naphthalen-1-yl]ethyl chloride

Achiral seco-aminocyclopropylbenz[ 2,3-e] indoline and secohydroxycyclopropylbenz[ 2,3-e] indoline ( seco-CBI) analogues of the duocarmycins and CC-1065, e. g., 7 and 8, are potent anticancer agents. This paper describes significantly improved synthetic strategies for preparing these compounds. Starting from Martius acid ( 9), the new strategy gave a 13-fold increase in the overall yield of 7, and the use of ditertbutyl malonate was economically beneficial. For compound 8, the new strategy employed an Emmons-Horner reaction, followed by a Stobbe condensation, and the overall yield was improved 15-fold.