13C NMR as a general tool for the assignment of absolute configuration
作者:Iria Louzao、José Manuel Seco、Emilio Quiñoá、Ricardo Riguera
DOI:10.1039/c0cc02774j
日期:——
(13)C NMR, alone or in combination with (1)H NMR, allows the assignment of the absolute configuration of chiral alcohols, amines, carboxylic acids, thiols, cyanohydrins, sec,sec-diols and sec,sec-aminoalcohols, derivatized with appropriate chiral auxiliaries. This extends the assignment possibilities of NMR to fully deuterated and to nonproton containing compounds.
Enzyme catalysed formation of (S)-cyanohydrins derived from aldehydes and ketones in a biphasic solvent system
作者:Herfried Griengl、Norbert Klempier、Peter Pöchlauer、Michael Schmidt、Nongyuan Shi、Antonina A Zabelinskaja-Mackova
DOI:10.1016/s0040-4020(98)00901-6
日期:1998.11
By employing a vigorously stirred two phase system aqueous buffer/organic solvent and using the hydroxynitrilelyase from Hevea brasiliensis as biocatalyst enantiopure (S)-cyanohydrins from aliphatic, unsaturated, aromatic and heteroaromatic aldehydes and methyl alkyl and methyl phenyl ketones are obtained in high yield and in general 98–99% enantiomeric excess.
The Use of a Single Derivative in the Configurational Assignment of Ketone Cyanohydrins
作者:Iria Louzao、José M. Seco、Emilio Quiñoá、Ricardo Riguera
DOI:10.1002/ejoc.201001107
日期:2010.12
The absolute stereochemistry of ketone cyanohydrins can be easily determined by preparing a single MPA derivative. The comparison of two NMR spectra at different temperatures allows the assignment by just paying attention to the evolution of the cyanohydrin chemical shifts. The special case of α-aryl-substituted cyanohydrins is also described.