PPh3‐Mediated Wittig‐Like/Mannich Tandem Reactions of 2‐Alkynylnitrobenzenes with Ketones for the Synthesis of 2,2‐Disubstituted Indolin‐3‐Ones

A synthetic strategy for the construction of 2,2‐disubstituted indolin‐3‐ones from 2‐alkynylnitroarenes and ketones has been described. The corresponding indolin‐3‐one derivatives were afforded in moderate to excellent product yields by using mild conditions. After a Wittig‐like process, the key intermediates 3H‐indol‐3‐ones were generated from 2‐alkynylnitroarenes, which could be further transformed to the desired products through a Mannich addition.