459174-06-2Relevant academic research and scientific papers
Asymmetric synthesis of 1,2,3-trisubstituted cyclopentanes and cyclohexanes as key components of substance P antagonists
Kuethe, Jeffrey T.,Wong, Audrey,Wu, Jimmy,Davies, Ian W.,Dormer, Peter G.,Welch, Christopher J.,Hillier, Michael C.,Hughes, David L.,Reider, Paul J.
, p. 5993 - 6000 (2007/10/03)
An efficient asymmetric synthesis of 1,2,3-trisubstituted cyclopentanes and cyclohexanes is described. Three methods were developed for the preparation of the 2,3-disubstituted cyclopentenones and cyclohexenones, which are key achiral building blocks. These intermediates are reduced catalytically with (R)-2-methyloxazaborolidine in high yield (82-98%) and excellent ee (89-96%). Directed reduction of the chiral allylic alcohols using Red-Al gives exclusively the 1,2-anti stereochemistry (>99:1). Epimerization of the ester center followed by saponification/crystallization affords the desired hydroxyacids in good yield (65-70%) and in high enantiomeric excess (>99%).
