[bmim][Br] as an Inexpensive and Efficient Medium for the Barbier-Type Allylation Reaction Using a Catalytic Amount of Indium: Mechanistic Studies

Nitrogen-Doped Carbon-Incarcerated Zinc Electrodes as Heterogeneous Catalysts for Electrochemical Allylation of Carbonyl Compounds

Electrochemical allylation reactions of carbonyl compounds using cathodes prepared from nitrogen-doped carbon (NDC)-incarcerated zinc catalysts have been developed. A range of aldehydes and ketones afforded the desired allylic alcohols in high yields with <10 mol % zinc leaching, and the heterogeneous nature of the active species was suggested. Compared with bulk zinc electrodes, NDC-stabilized zinc nanoparticle species were compatible with a broader range of heteroaromatic substrates and enabled the use of an undivided cell.

Direct use of 1,3-dienes for the allylation of ketones via catalytic hydroindation

In this study, in situ catalytically generated allylic indium from 1,3 dienes and InCl₂H was developed for use in the allylation of ketones.

Bi-mediated allylation of aldehydes in [bmim][Br]: a mechanistic investigation

The inexpensive room temperature ionic liquid (RTIL), [bmim][Br] has been found to be a superior medium for the Bi-mediated Barbier-type allylation of aldehydes compared to other conventional solvents. It plays the dual role of a solvent and a metal activator enabling higher yields of the products in a shorter reaction time using stoichiometric/near-stoichiometric amounts of reagents. Plausibly, [bmim][Br] activates Bi metal by a charge transfer mechanism. The ¹H VT-NMR studies suggested that both the allylating species, allylbismuth dibromide and diallylbismuth bromide, are generated in situ.

Indium-Mediated Allylation of Carbonyl Compounds in Ionic Liquids: Effect of Salts in Ionic Liquids

The In-mediated allylation of carbonyl compounds can be performed in various types of solvents including ionic liquids. However, we have found that in [bmim][BF₄] (where bmim = 1-butyl-3-methylimidazolium), the In-mediated coupling of crotyl bromide with benzaldehyde gives a complex mixture, and some additives, such as halides and amines, are crucial for the successful conversion to the corresponding γ-adduct. Instead, the addition of alcohols or water promotes the formation of the α-adduct. An asymmetric induction with up to 62% enantiomeric excess (ee) was observed employing cinchonidine as an additive in a binary solvent consisting of an ionic liquid and dichloromethane.