Use of a Chiral Surfactant for Enantioselective Reduction of a Ketone
Document Type
Article
Publication Date
8-15-2004
Description
The influence of a chiral surfactant and a polymer-supported chiral additive on reduction of ketones using sodium borohydride will be described. Initial preparations involved methylation of (S)-leucinol to give (2S)-N,N-dimethyl-2-amino-4-methyl-1-pentanol (1) (67%). The chiral surfactant (2) was synthesized by reacting (1) with bromohexadecane (71%). The functionalized styrene for the polymer-supported chiral additive (5) was synthesized by reacting (1) with 4-vinylbenzyl chloride. Polymerization was carried out with 10% of the functionalized monomer (4), 5% cross-linking agent divinylbenzene, and 85% styrene with AIBN as the initiator. The activity of the chiral surfactant and polymeric additive were examined by using them as additives in a standard reduction of 2-pentanone with sodium borohydride to yield (R)- and (S)-2-pentanol (3) (20%). The resulting alcohol was analyzed by polarimetry (ee 9.5%) and also esterified with (2S)-methylbutyric acid prior to characterization by NMR. 13C NMR indicated an enantiomeric excess of 5.2% when the chiral surfactant was used, and 7% when the polymeric additive was used.
Citation Information
Davidson, Tammy A.; Mondal, Kalyan; and Yang, Xiaoye. 2004. Use of a Chiral Surfactant for Enantioselective Reduction of a Ketone. Journal of Colloid and Interface Science. Vol.276(2). 498-502. https://doi.org/10.1016/j.jcis.2004.03.053 ISSN: 0021-9797