Mannich-Type Reaction Promoted by an Ionic Liquid

Abstract

The Mannich-type reaction of silyl enolates with ald­imines occurred smoothly with [emim]OTf as a solvent and without the addition of an activator to afford β-amino carbonyl compounds in excellent yields.

Key words

ionic liquids - Mannich reaction - imine - catalysis

References

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13

We have already reported that a catalytic amount of Brønsted acid promoted the Mannich-type reaction. [3]

14

The Mannich-type reaction of 1a and 2a did not proceed in conventional organic solvents such as Et₂O, CH₂Cl₂, CH₃CN, CH₃OH, or toluene.

15

Due to the fact that [emim]OTf does not dissolve in EtOAc-hexane (4:1), recycling of the ionic liquid is easier than for [bmim]OTf.