A Bioinspired Synthesis of Polyfunctional Indoles

Abstract

Polyfunctional indoles bearing substituents at C5 and C6 are prevalent in natural products, pharmaceuticals, agrochemicals, and materials. Owing to the remoteness of the C5 and C6 positions, indoles of this family can be difficult to prepare, and often require multistep syntheses. Herein, we describe a concise process that converts simple derivatives of tyrosine into 5,6-difunctionalized indoles by direct oxidation of C-H, N-H, and O-H bonds. Our work draws inspiration from the biosynthetic polymerization of tyrosine to make melanin pigments, but makes an important departure to provide well-defined indole heterocycles.

Keywords: C−H functionalization; aerobic catalysis; copper catalysis; indoles; melanogenesis.