Harnessing Deep Eutectic Solvents for Regioselective Polar Additions to α, β Unsaturated Ketones and Aldehydes.

Advancing the use of air-sensitive polar organometallic Grignard and organolithium reagents under more environmentally benign conditions, here we report the addition of these reagents to α,β-unsaturated ketones and aldehydes using the deep eutectic solvent (DES) choline chloride (ChCl): glycerol (Gly) (1 : 2), under air. Reactions occur at room temperature within seconds with excellent regioselective control. Furthering understanding of how these C-C bond forming processes take place in these reaction media, we have explored the surface concentration of the organic substrate (chalcone) in DES using interfacial tension and neutron reflectivity measurements, finding that chalcone is concentrated at the DES-hydrocarbon interface compared to the bulk concentration, although the interfacial chalcone concentration is still relatively low in this system.

Structural and Synthetic Insights on Oxidative Homocouplings of Alkynes Mediated by Alkali-Metal Manganates.

Exploiting bimetallic cooperation alkali-metal manganate (II) complexes can efficiently promote oxidative homocoupling of terminal alkynes furnishing an array of conjugated 1,3-diynes. The influence of the alkali-metal on these C-C bond forming processes has been studied by preparing and structurally characterizing the alkali-metal tetra(alkyl) manganates [(TMEDA) Na Mn(CH SiMe ) ] and [(PMDETA) K Mn(CH SiMe ) ]. Reactivity studies using phenylacetylene as a model substrate have revealed that for the homocoupling to take place initial metalation of the alkyne is required.