TY - JOUR
T1 - 'Watching' lipase-catalyzed acylations using 1H NMR
T2 - Competing hydrolysis of vinyl acetate in dry organic solvents
AU - Weber, Hedda K.
AU - Weber, Hansjörg
AU - Kazlauskas, Romas J.
PY - 1999/7/16
Y1 - 1999/7/16
N2 - Lipase-catalyzed acetylations of 1-phenylethanol with vinyl acetate were monitored in situ by 1H NMR spectroscopy. Surprisingly, even under dry conditions (no added water) the major reaction was hydrolysis of the vinyl acetate, not acetylation of the substrate. Because this competing hydrolysis consumes water and releases acetic acid, the reaction conditions in lipase-catalyzed acylations are not constant, but vary with the reaction time. Addition of a chiral shift reagent reveals the enantiomeric purity of the starting alcohol and allows calculation of the enantiomeric ratio, E, for the reaction.
AB - Lipase-catalyzed acetylations of 1-phenylethanol with vinyl acetate were monitored in situ by 1H NMR spectroscopy. Surprisingly, even under dry conditions (no added water) the major reaction was hydrolysis of the vinyl acetate, not acetylation of the substrate. Because this competing hydrolysis consumes water and releases acetic acid, the reaction conditions in lipase-catalyzed acylations are not constant, but vary with the reaction time. Addition of a chiral shift reagent reveals the enantiomeric purity of the starting alcohol and allows calculation of the enantiomeric ratio, E, for the reaction.
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U2 - 10.1016/S0957-4166(99)00274-8
DO - 10.1016/S0957-4166(99)00274-8
M3 - Article
AN - SCOPUS:0033575391
VL - 10
SP - 2635
EP - 2638
JO - Tetrahedron Asymmetry
JF - Tetrahedron Asymmetry
SN - 0957-4166
IS - 14
ER -