TY - DATA T1 - Diastereoselective Alkylation of β-Amino Esters:  Structural and Rate Studies Reveal Alkylations of Hexameric Lithium Enolates PY - 2004/12/22 AU - Anne J. McNeil AU - Gilman E. S. Toombes AU - Sol M. Gruner AU - Emil Lobkovsky AU - David B. Collum AU - Sithamalli V. Chandramouli AU - Benoit J. Vanasse AU - Timothy A. Ayers UR - https://acs.figshare.com/articles/dataset/Diastereoselective_Alkylation_of_Amino_Esters_Structural_and_Rate_Studies_Reveal_Alkylations_of_Hexameric_Lithium_Enolates/3311167 DO - 10.1021/ja045144i.s002 L4 - https://ndownloader.figshare.com/files/5149900 KW - Single crystal KW - rate studies show KW - THF KW - 6 Li NMR spectroscopic studies KW - enolate show KW - heterochiral hexamers KW - racemic enolate forms prismatic hexamers KW - racemic enolates KW - energy differences KW - ester enolates proceeds KW - Boltzmann distribution KW - Diastereoselective Alkylation KW - Rate Studies Reveal Alkylations KW - enolate alkylation KW - equilibrium constants KW - Hexameric Lithium Enolates Alkylation N2 - Alkylation of β-amino ester enolates proceeds with high diastereoselectivity. Single crystal, powder, and solution X-ray diffraction studies of the enolate show that the racemic enolate forms prismatic hexamers. 6Li NMR spectroscopic studies on partially racemic enolates reveal complex mixtures of homo- and heterochiral hexamers. An implicit fit of the aggregate populations to the Boltzmann distribution provides the free energy differences and equilibrium constants for the ensemble. Rate studies show that enolate alkylation occurs directly from the hexamer with participation by THF. A mechanism based on the alkylation of a ladder-like aggregate is proposed. ER -