Researchers of the Zelinsky Institute have proposed a reagent for the photocatalytic activation of the carbon-halogen bond

The breaking of the carbon-halogen bond is quite widely used to generate organic carbon-centered radicals. Among the alkyl halides, chlorine derivatives are the most accessible, but they are also the least reactive. In recent decades, photoredox catalysis has been actively used to break the carbon-halogen bond, which made it possible to avoid the use of highly toxic organotin compounds. Within this direction, the concept of halogen atom transfer (XAT) using α-aminoalkyl radicals was proposed several years ago. These intermediates are formed from readily available tertiary amines and effectively activate alkyl iodides and fluorinated bromides, however, no examples of carbon-chlorine bond breaking by this method have been developed.

Scientists of the Laboratory of Functional Organic Compounds of ZIOC are actively engaged in the study of free radical transformations under photoredox catalysis conditions. The researchers suggested that in the processes of halogen atom transfer, the transition from amines to aminals can lead to an increase in the efficiency of the reaction due to the additional donor action of the second nitrogen atom on the radical center. In one of their latest work, they showed that 1,3,5-triazinane exhibits a very high reactivity as a HAT reagent due to its cyclic structure and stereoelectronic effects. Using the proposed approach, scientists have successfully implemented the reaction of hydrofluoroalkylation of alkenes with fluorinated alkyl chlorides.
 

Source:

Vladislav S. Kostromitin, Artem O. Sorokin, Vitalij V. Levin, Alexander D. Dilman Aminals as powerful XAT-reagents: activation of fluorinated alkyl chlorides // Chem. Sci., 2023, accepted manuscript. DOI: 10.1039/d3sc00027c.