Asymmetric Carbonyl Addition and Asymmetric Polymerization Assisted by Axially Chiral Diamines Give Disparate Ligand/Product Configurational Correlations

Abstract

Organolithium reagents complexed with axially chiral biphenyl-substituted N,N,N′,N′-tetramethylethylenediamines (1 and 2) add to aldehydes in good enantioface selectivity. The pattern of the stereoselection, however, disagrees with that of the helical choice observed for the asymmetric polymerization of triphenylmethyl methacrylate with the same complexes.

Chiral Tertiary Diamines in Asymmetric Synthesis

“…Again, addition of phenyllithium to valeraldehyde was much less efficient leading to the alcohol in only 18% ee. 197 Although many 3-aminopyrrolidines lithium amides were used for this reaction, only one example of a tertiary diamine was reported. Diamine 335 was used for the addition of benzaldehyde to o-tolualdehyde leading to the racemic alcohol in quantitative yield, whereas analogues having a secondary-tertiary diamine structure led to the product in 80% ee.…”

“…In the classic case of the addition of n- butyllithium to benzaldehyde, ( R , R )- 336 at −120 °C produced the R alcohol in 99% ee. Again, addition of phenyllithium to valeraldehyde was much less efficient leading to the alcohol in only 18% ee …”