Synthesis of new C1-symmetric bis(oxazoline) ligands with a chelating sidearm for stereoselective Mukaiyama aldol condensations

Novel C1-symmetric bis(oxazoline) ligands with a secondary binding sidearm were prepared in enantiomerically pure form in good yields, in only four steps starting from commercially available reagents. These new chiral ligands were tested in the enantioselective Mukaiyama aldol condensation between the trimethylsilyl keteneacetal of methyl isobutyrate and a non-chelating substrate such as benzaldehyde to afford the product in up to 55% ee.

Graphical abstractNew enantiomerically pure C1-symmetric bis(oxazoline) ligands with a binding sidearm were synthesised in good yields and tested in the stereoselective Mukaiyama aldol condensation between the trimethylsilyl keteneacetal of methyl isobutyrate and a non-chelating substrate such as benzaldehyde to afford the product in up to 55% ee.Figure optionsDownload full-size imageDownload as PowerPoint slide