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