Metal‐Free Synthesis of Oxa Spiro‐indene‐1,3‐dione Tetrahydrofurans and Pyrans via [3+2]/[4+2] Spirocyclization of 2‐Arylidene‐1,3‐indanedione With Haloalcohols
A concise and efficient method has been developed for the synthesis of pharmacologically important spiro‐indene‐1,3‐dione‐ fused tetrahydrofurans and pyrans via a base‐mediated cascade [3+2]/[4+2] spirocyclization of 2‐arylidene‐1,3‐indandiones and 2‐(3‐phenylallylidene)‐indandione with haloalcohols. This protocol of...