Iridium Porphyrin-Catalyzed Asymmetric Rearrangement of Oxindoles with Aryl Diazoesters: Enantioselective Synthesis of Chiral Tertiary 2-Indolyl Alcohols.

The asymmetric functionalization of indoles at the C2 position to afford chiral tertiary alcohols poses a formidable challenge in organic synthesis, primarily due to the inherent preference for C3 reactivity. Herein, we report the asymmetric generation and transformation of carbonyl ylides from oxindoles using a β-aryl axially chiral iridium porphyrin complex. This system enables a highly site-selective and enantioselective reaction between oxindoles and aryl diazoesters, involving enantioselective carbonyl ylide formation, tandem epoxidation, and rearrangement. The process efficiently provides a series of chiral tertiary 2-indolyl alcohols that are difficult to access via direct Friedel-Crafts alkylation of indoles.