Abstract: Efficient rhodium-catalyzed Sommelet-Hauser type rearrangement of 3-diazoindolin-2-ones with α-thioesters has been accomplished for the synthesis of C4-thioalkylated oxindoles. The developed reaction offers the selective functionalization of C4-position of oxindole via generation of S-ylide and [2, 3]-sigmatropic rearrangement and allows access to diverse C4-thioalkylated oxindoles in good to excellent yield. Furthermore, the method was successfully extended to the synthesis C4-selenoalkylated oxindoles employing the corresponding α-selenoester. Graphic abstract: Efficient rhodium-catalyzed Sommelet-Hauser type rearrangement of 3-diazoindolin-2-ones with α-thio/α-seleno-esters have been disclosed for the synthesis of C4-thio/selenoalkylated oxindoles.[Figure not available: see fulltext.]. © 2019, Indian Academy of Sciences.