Photoredox Cyanomethylation of Indoles: Catalyst Modification and Mechanism.
J Org Chem
; 83(16): 8926-8935, 2018 08 17.
Article
in En
| MEDLINE
| ID: mdl-29940725
ABSTRACT
The direct cyanomethylation of indoles at the 2- or 3-position was achieved via photoredox catalysis. The versatile nitrile synthon is introduced as a radical generated from bromoacetonitrile, a photocatalyst, and blue LED as a light source. The mechanism of the reaction is explored by determination of the Stern-Volmer quenching constants. By combining photophysical data and mass spectrometry to follow the catalyst decomposition, the catalyst ligands were tuned to enable synthetically useful yields of radical coupling products. A range of indole substrates with alkyl, aryl, halogen, ester, and ether functional groups participate in the reaction, affording products in 16-90% yields. The reaction allows the rapid construction of synthetically useful cyanomethylindoles, products that otherwise require several synthetic steps.
Full text:
1
Database:
MEDLINE
Main subject:
Photochemical Processes
/
Indoles
/
Nitriles
Language:
En
Year:
2018
Type:
Article