Novel Arylindigoids by Late‐Stage Derivatization of Biocatalytically Synthesized Dibromoindigo

Schnepel, Christian; Dodero, Veronica I.; Sewald, Norbert

Abstract

Indigoids represent natural product-based compounds applicable as organic semiconductors and photoresponsive materials. Yet modified indigo derivatives are difficult to access by chemical synthesis. A biocatalytic approach applying several consecutive selective C−H functionalizations was developed that selectively provides access to various indigoids: Enzymatic halogenation of l-tryptophan followed by indole generation with tryptophanase yields 5-, 6- and 7-bromoindoles. Subsequent hydroxylation using a flavin monooxygenase furnishes dibromoindigo that is derivatized by acylation. This four-step one-pot cascade gives dibromoindigo in good isolated yields. Moreover, the halogen substituent allows for late-stage diversification by cross-coupling directly performed in the crude mixture, thus enabling synthesis of a small set of 6,6’-diarylindigo derivatives. This chemoenzymatic approach provides a modular platform towards novel indigoids with attractive spectral properties.

Citation

Schnepel, C., Dodero, V. I., & Sewald, N. (2021). Novel Arylindigoids by Late‐Stage Derivatization of Biocatalytically Synthesized Dibromoindigo. Chemistry - A European Journal, 27(17), 5404-5411. https://doi.org/10.1002/chem.202005191

• Journal Article Type: Article
• Acceptance Date: Jan 26, 2021
• Online Publication Date: Feb 26, 2021
• Publication Date: Mar 22, 2021
• Deposit Date: Jan 1, 2025
• Journal: Chemistry – A European Journal
• Print ISSN: 0947-6539
• Electronic ISSN: 1521-3765
• Publisher: Wiley
• Peer Reviewed: Peer Reviewed
• Volume: 27
• Issue: 17
• Pages: 5404-5411
• DOI: https://doi.org/10.1002/chem.202005191
• Public URL: https://durham-repository.worktribe.com/output/3263837