Christine Baudequin

Ionic liquids and chirality: opportunities and challenges

This review deals with recent advances in the investigation of ionic liquids (ILs) in the field of chirality, i.e. asymmetric synthesis and new chiral solvents.

Synthesis and Photophysical Investigation of a Series of Push–Pull Arylvinyldiazine Chromophores

A new series of push-pull arylvinyldiazines has been efficiently prepared by aldol condensation between the appropriate methyldiazine and aromatic aldehyde. The optical absorption and emission properties of these chromophores were studied in different solvents and media. These compounds act as polarity sensors with a strong positive emission solvatochromism. This behavior suggests a highly polar emitting state, which is characteristic of compounds that undergo an internal charge transfer upon excitation. These molecules also exhibit halochromic properties and are potential colorimetric and luminescence pH sensors. The second-order nonlinear properties have been investigated for some of the compounds, and large and positive μβ are obtained, in particular, for pyrimidine derivatives.

Enantioselective electrophilic fluorination: a study of the fluorine-transfer from achiral N–F reagents to cinchona alkaloids

Abstract A transfer fluorination on cinchona alkaloids with the aid of achiral N–F fluorine-transfer reagents is described. Ten commercially available reagents were evaluated. Selectfluors™ 9 and 10 , Accufluor™ 11 , N -fluorobenzenesulfonimide (NFSi) 13 , and N -fluoro-2,6-dichloropyridinium tetrafluoroborate 17 are effective fluorine-transfer reagents. The N -fluoroammonium salts of cinchona alkaloids thus prepared were employed in the construction of stereogenic fluorinated carbon centers with enantioselectivity as high as 85%. We also demonstrated that ionic liquids are effective “green” solvents for the development of this methodology.

Enantioselective electrophilic fluorination in ionic liquids

It has been demonstrated that enantioselective electrophilic fluorination performed by means of N-fluorocinchonium salts in ionic liquids presents substantial advantages over the use of classical solvents.

Pd(0)‐Catalyzed Direct C−H Functionalization of 2‐H‐4‐Benzylidene Imidazolones: Friendly and Large‐Scale Access to GFP and Kaede Protein Fluorophores

The first one-pot synthesis of N-substituted 2-H-4-benzylidene imidazolones and their subsequent palladium-catalyzed and copper-assisted direct C2-H arylation and alkenylation with aryl- and alkenylhalides are described. This innovative synthesis is step-economical, azide-free, high yielding, highly flexible in the introduction of a variety of electronically different groups, and can be operated on large-scale. Moreover, the method allows direct access to C2-arylated or alkenylated imidazolone-based green fluorescent protein (GFP) and Kaede protein fluorophores, including ortho-hydroxylated models.