Abstract
A dearomative oxidation of pyrroles to Δ3-pyrrol-2-ones is described, which employs a sulfoxide as oxidant, in conjunction with a carboxylic acid anhydride and a Brønsted acid additive. 3-substituted pyrroles undergo regioselective oxidation to give the product isomer in which oxygen has been introduced at the more hindered position. Regioselectivity is rationalized by a proposed mechanism that proceeds by initial thianthrenium introduction at the less-hindered pyrrole α-position, followed by distal attack of an oxygen nucleophile and subsequent elimination of thianthrene. The same reaction conditions are also able to effect a chemoselective oxidation of indoles to indolin-3-ones and additionally of indolin-3-ones to 2-hydroxyindolin-3-ones. Here again, the regio- and chemoselectivities are rationalized through the intermediacy of a thianthrenium salt.
| Original language | English |
|---|---|
| Article number | e202405057 |
| Journal | Angewandte Chemie International Edition |
| Volume | 63 |
| Issue number | 33 |
| Early online date | 3 Jun 2024 |
| DOIs | |
| Publication status | Published - 12 Aug 2024 |
Data Availability Statement
The data that support the findings of this study are available in the supplementary material of this article.Funding
The authors thank EPSRC for funding (EP/W036193/1) and for a DTP PhD studentship to J.L.H. (EP/T518013/1). The authors acknowledge the research facilities at the University of Bath ( https://doi.org/10.15125/mx6j\u20103r54 ). This work used the Isambard 2 UK National Tier\u20102 HPC Service ( http://gw4.ac.uk/isambard/ ) operated by GW4 and the UK Met Office, and funded by EPSRC (EP/T022078/1).
| Funders | Funder number |
|---|---|
| EPSRC - EU | EP/T518013/1, EP/W036193/1 |
Keywords
- indolin-3-one
- interrupted Pummerer
- pyrrol-2-one
- thianthrenium
ASJC Scopus subject areas
- Catalysis
- General Chemistry