3-Aminopyrrolidine lithium

Among other enantioselective alkylations, a series of 3-aminopyrrolidine lithium amides (67 derived from 4-hydroxy-L-proline) have been used to induce high ee% in the addition of alkyllithiums to various aldehydes. Structure-activity relationships are identified, and the role of a second chiral centre (in the R group) in determining the stereochemistry of the product is discussed. 

Enantiomeric excesses of up to 76% have been obtained for alkyllithium-aldehyde condensations using 3-aminopyrrolidine lithium amides as chiral auxiliaries. Addition of organolithiums to imines has been achieved with up to 89% ee, in the presence of C2-symmetric bis(aziridine) ligands. ... 

Mixed aggregates of chiral lithium amide and lithium ester enolate have been employed in the enantioselective conjugate addition on a,/S-unsaturated esters.27 Michael adducts have been obtained in ees up to 76% combining a lithium enolate and a chiral 3-aminopyrrolidine lithium amide. The sense of the induction has been found to be determined by both the relative configuration of the stereogenic centres borne by the amide and the solvent. 

Note added in proof. Complexes between MeLi and Chiral 3-aminopyrrolidine lithium amides bearing a second asymmetric center on their lateral amino group have been studied using multinuclear low-temperatme NMR spectroscopy, and a relationship between the topology of these complexes and the sense of induction in the enantioselective alkylation of aaromatic aldehydes by alkyllithiums has been proposed [115], 1,2-Amino sulfides have been used as chiral ligands in the enantioselective addition of BuLi and MeLi to various aldehydes (PhCHO, EtCHO) at low temperatures in up to 98.5% ee [16],... 

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