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

Abstract

Asymmetric catalytic ethylation of benzaldehyde utilizing a series of new, artificial β-amino alcohols based on the octahydro-cyclopenta[ b]pyrrole system is presented. A systematic investigation on the inductive correlation of up to four catalyst-internal stereogenic centers and on steric aspects of these structures has been conducted with diastereomerically pure, bicyclic ( erythro)- and ( threo)-compounds 2–13. Chiral ligands have been developed reaching excellent enantioselectivities, e.g. enantiomeric excesses up to 91% with a favored ( R)-induction.