Experimental and Theoretical Study of an Intramolecular CF3-Group Shift in the Reactions of α-Bromoenones with 1,2-Diamines

Synthesis of 5-(trifluoroacetyl)imidazoles from Bromoenones and Benzimidamides via Aza-Michael Initiated Ring Closure Reaction

INTRODUCTION

A simple method for the preparation of 5-(trifluoroacetyl)imidazoles was elaborated.

METHODS

The reaction of trifluoromethyl(α-bromoalkenyl)ketones with benzimidamides was employed to afford the target heterocycles in good yields.

RESULTS

The assembly of imidazole core proceeds via aza-Michael adduct formation followed by intramolecular nucleophilic substitution and spontaneous aromatization as an oxidation sequence.

CONCLUSION

The yields of target imidazoles can be improved by the use of soft oxidizing agents.

Construction of multiple bonds via a domino reaction of trifluoroacetimidoyl nitriles with in situ generated bis-nucleophiles

A transition-metal-free double addition/double rearrangement domino reaction affording CF3-substituted pyrimidines was developed, which enables the one-pot construction of five new bonds, namely three C-C bonds and two C-N bonds. The keys to achieve this highly efficient reaction include the delicate design of the bis-nucleophiles in situ generated from the dimerization of alkyl nitriles and the use of trifluoroacetimidoyl nitriles containing C[double bond, length as m-dash]N, C[triple bond, length as m-dash]N, and CF3 groups as the reactant. The mechanistic studies by the experiments and DFT calculations reveal that the transformation involves two addition and two unprecedented rearrangement processes.

Unsaturated polyfluoroalkyl ketones in the synthesis of nitrogen-bearing heterocycles

This review focuses on the recent achievements and new developments in the synthesis of polyfluorinated aza-heterocycles based on fluorine-bearing enones and ynones published in the last decade.