First asymmetric synthesis of both enantiomers of Tropional® and their olfactory evaluation
摘要:
The first asymmetric synthesis of both enantiomers of Tropional(R) is accomplished by asymmetric alkylation by employing the SAMP/RAMP-hydrazone method, respectively. The alkylated hydrazones were oxidatively cleaved with magnesium-monoperoxyphthalate (MMPP). Subsequent reduction of the resulting nitriles with diisobutyl aluminium hydride (DIBAL-H) led to the desired aldehydes in good overall yields (52-53%) and enantiomeric excesses (ee = 90%). Furthermore, the olfactory evaluation of both enantiomers showed remarkable differences in odour quality and intensity. (C) 2004 Elsevier Ltd. All rights reserved.
A cyanide‐free platform technology for the synthesis of chiral nitriles by biocatalytic enantioselective dehydration of a wide range of aldoximes is reported. The nitriles were obtained with high enantiomeric excess of >90 % ee (and up to 99 % ee) in many cases, and a “privileged substrate structure” with respect to high enantioselectivity was identified. Furthermore, a surprising phenomenon was observed
First asymmetric synthesis of both enantiomers of Tropional® and their olfactory evaluation
作者:Dieter Enders、Michael Backes
DOI:10.1016/j.tetasy.2004.04.026
日期:2004.6
The first asymmetric synthesis of both enantiomers of Tropional(R) is accomplished by asymmetric alkylation by employing the SAMP/RAMP-hydrazone method, respectively. The alkylated hydrazones were oxidatively cleaved with magnesium-monoperoxyphthalate (MMPP). Subsequent reduction of the resulting nitriles with diisobutyl aluminium hydride (DIBAL-H) led to the desired aldehydes in good overall yields (52-53%) and enantiomeric excesses (ee = 90%). Furthermore, the olfactory evaluation of both enantiomers showed remarkable differences in odour quality and intensity. (C) 2004 Elsevier Ltd. All rights reserved.
Crystal structural analysis of aldoxime dehydratase from Bacillus sp. OxB-1: Importance of surface residues in optimization for crystallization
However sufficient structural information to discuss the substrate specificity has not been obtained. Oxd from Bacillus sp. OxB-1 (OxdB) shows unique substrate specificity and enantioselectivity compared to the Oxds whose crystalstructures have already been reported. Here, we report the crystalstructure of OxdB, which has not been reported previously. Although the crystallization of OxdB has been difficult