98203-46-4Relevant academic research and scientific papers
Stereoselective alkylations in rigid systems. Effect of remote substituents on π-facial additions to lactam enolates. Stereoelectronic and steric effects
Meyers,Seefeld, Mark A.,Lefker, Bruce A.,Blake, James F.,Williard, Paul G.
, p. 7429 - 7438 (2007/10/03)
A series of chiral bicyclic lactams has been studied by both experiment and ab initio molecular orbital calculations, The facial selectivity of the alkylation of their enolates shows a high degree of endo or exo entry, depending upon certain substituents and their positions in the lactams. The suggested reasons for the exo or endo selectivity for alkylation were determined to be purely electronic or purely steric in certain instances, The results of the selectivity study now allow the asymmetric synthesis of various ketones, acids, and pyrrolidines in either enantiomeric form based on the choice of lactam employed.
Synthesis of Enantiomerically Pure Hydrinden-2-ones and Benzinden-2-ones via Asymmetric Alkylations of Chiral Bicyclic Lactams
Snyder, Lawrence,Meyers, A. I.
, p. 7507 - 7515 (2007/10/02)
A route to the titled compounds in >99percent ee was achieved from sequential diastereoselective alkylations of chiral, nonracemic bicyclic lactams 6 and 15.An intramolecular addition of the organolithium species derived from 17a-c and 28a-d gave, after hydrolysis, diketones 25a-c and 30a-d, which were cyclized to the titled compounds 4a-c and 31a-d.As an example of the versatility of this method, the ABC ring system of the triterpene stelliferin A, isolated from marine organisms, was prepared in high enantiomeric excess.
