Figure 4.

a) The N‐Ac CBI double prodrug 5 reacting with 2 c leading to the formation of the intermediate 6 which undergoes a Winstein spirocyclization to afford the bioactive cyclopropanyl 7. b) General protocol for 2 c‐mediated intracellular decaging of 5. c) HPLC time‐course of the reaction between 5 and 2 c. d) Half maximal inhibitory concentration (IC₅₀) of 2 c, 5, and 7 in A549 and HepG2 cells. e) Cytotoxicity fitted dose‐response curves of 2 c, 5, and 7 in A549 cells, obtained after 46 hours 30 min of exposure. f) Cytotoxic effects of intracellular activation of the prodrug 5 by 2 c inside A549 cells. For data on HepG2 cells, see the Supporting Information.