Ppm Cu Catalyst Enables tert-Alkylation Followed by C–H Cyclization To Synthesize Substituted Oxindoles

[Image: see text] In this paper, we established highly efficient Cu-catalyzed tandem tert-alkylation C–H cyclization of α-bromocarbonyls and methacrylamides to produce substituted oxindoles. The maximum turnover number was up to 48 000 with reasonable yield. Although the catalyst loadings were very low, the reaction was not involving radical chain reaction. The resulting oxindoles were able to transform into aza-multicyclic compound via a reduction.