A Facile,Atom‐Economical,and One‐Pot Pseudo Four‐Component Synthesis of Isoxazolylspiro[diindeno[1,2‐b;2′,1′‐e]pyridine‐11,3′‐indoline]‐2′,10,12‐triones Catalyzed by pTSA

A facile, atom‐economical, and one‐pot pseudo four‐component method for the synthesis of isoxazolylspirodiindeno1,2‐b ;2′,1′‐e ]pyridine‐11,3′‐indoline]‐2′,10,12‐trione derivatives ( 14 ) is described. Prominent advantages of this new method are operational simplicity, excellent yields with high purity, short reaction time, easy workup, and mild conditions.