Structures of beta-amino ester enolates: new strategies using the method of continuous variation.
The solution structures of four enolates derived from beta-amino esters are investigated using (6)Li NMR spectroscopy in conjunction with the method of continuous variation (method of Job). Ensembles of homo- and heteroaggregated enolates are generated by mixing enantiomers of a single enolate (R/S mixtures), opposite antipodes of two different enolates (R/S' mixtures), and the same antipodes of two different enolates (R/R' mixtures). The numbers of observable aggregates and their dependence on the mole fraction of the two enolates confirm the hexamer assignments. Inherent symmetries observable in the (6)Li NMR spectra show the stereochemistry of chelation about the hexagonal drum.
Liou
Lara R
LR
Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301, USA.
McNeil
Anne J
AJ
Toombes
Gilman E S
GE
Collum
David B
DB
D002625:Chemistry, Organic / Q000379:methods*; D015195:Drug Design; D004952:Esters / Q000737:chemistry*; D008094:Lithium / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical; D008958:Models, Molecular; D015233:Models, Statistical; D012984:Software; D013237:Stereoisomerism
D004952:Esters; D008094:Lithium