A Simple Method for Asymmetric Trifluoromethylation of N-Acyl Oxazolidinones via Ru-Catalyzed Radical Addition to Zirconium Enolates

Abstract

A Ru-catalyzed direct thermal trifluoromethylation and perfluoroalkylation of N-acyloxazolidinones has been developed. The reaction is experimentally simple and requires inexpensive reagents while providing good yields of products with good levels of stereocontrol. Preliminary studies have shown notable compatibility with functional groups, aromatics, and certain heteroaromatic substituents. The described method provides a useful alternative for the synthesis of fluorinated materials in an experimentally convenient manner.

Asymmetric photoredox transition-metal catalysis activated by visible light

“…4a. This structure also illustrates that one face of the prochiral enolate p-bond is blocked by a tert-butyl group, thereby rationalizing the observed high asymmetric induction in the course of the proposed diastereoselective addition of the electron-deficient radical to the electron-rich double bond 28 . The determined absolute configurations of the a-alkylation products are consistent with this mechanistic picture.…”

Recent advances in the trifluoromethylation methodology and new CF3-containing drugs

“…For this purpose, lithium enolates derived from N-acyl oxazolidinones (Evans chiral auxiliaries) easily reacted with Togni's reagent to provide the corresponding a-CF 3 products in excellent diastereomeric ratios [57] (Scheme 7). More recently, the parent zirconium enolates were prone to react with CF 3 I in a radical process promoted by a ruthenium catalyst [58]. As pointed out above, nucleophilic reagents such as CF 3 SiMe 3 may not be used for a-trifluoromethylations of carbonyl compounds.…”

Rhodium‐Catalyzed Enantioselective Radical Addition of CX4 Reagents to Olefins

“…Additionally, enolates coordinated to a chiral-at-metal Ir complex can combine with electrophilic trichloromethyl radicals [11] and electron-poor benzylic radicals. [12],[13] …”