Synthesis and application of new β-amino alcohols based on the octahydro-cyclopenta[b]pyrrole system in the catalytic enantioselective addition of diethylzinc to benzaldehyde

Starting from an industrial waste material, the synthesis of a series of new, artificial β-amino alcohol structures (all-R)-6–10 and 13–16 based on the octahydro-cyclopenta[b]pyrrole system is presented. These structures were also the subject of studies aimed at developing effective catalysts for enantioselective alkylation by diethylzinc. Attention was focussed on stereochemical and steric aspects of the catalyst (-precursor) structure. Potent chiral ligands have been developed reaching excellent enantioselectivities, e.g. op-values up to 99% with predominant formation of the (R)-configurated alkylation products.

The synthesis of various new β-amino alcohols e. g. 7 – 10 is described. The new compounds were found to be effective catalysts in the addition of diethylzine to benzaldehyde. The use of ligands 7 – 10 leads to optical purities between 94 and 99 % op.Figure optionsDownload full-size imageDownload as PowerPoint slide