Tandem ionic liquid antimicrobial toxicity and asymmetric catalysis study: carbonyl-ene reactions with trifluoropyruvate

Abstract

The asymmetric carbonyl-ene reaction of trifluoropyruvate with five alkenes catalysed by [Pd{(R)-BINAP}]-(SbF6)(2) were carried out in good yields and enantioselectivities (up to 96% yield and 96% ee) in low antimicrobial toxicity C2-substituted imidazolium ionic liquids (ILs). Toxicity data was included in the selection criteria for reaction optimisation after a preliminary IL screen.

The Pd(ii) catalyst immobilised in an IL was recycled and reused up to 7 times without decrease of either yield or ee. One IL prepared, which was determined to be of high antimicrobial toxicity was assigned a low priority for future applications.

Keywords

• alpha-hydroxy esters
• dicationic palladium(ii) complexes
• base chromium(iii) complexes
• flexible nuphos diphosphines
• high enantiomeric purities
• chiral lewis-acids
• enantioselective catalysis
• highly efficient
• copper(ii) complexes
• glyoxal derivatives