## Abstract magnified image The enantiomerically pure title compounds were prepared and the absolute configurations assigned by the high‐field ^1^H‐NMR application of the __Mosher__ method on the bis‐MTPA derivatives (MTPA=__α__‐methoxy‐__α__‐(trifluoromethyl)benzeneacetic acid). The final evidenc
The Absolute Configuration of (+)-Ethyl cis-1-Benzyl-3-hydroxypiperidine-4-carboxylate and (+)-4-Ethyl 1-Methyl cis-3-Hydroxypiperidine-1,4-dicarboxylate; a Revision
✍ Scribed by Piergiorgio A. Lorenzetto; Andreas Strehler; Peter Rüedi
- Publisher
- John Wiley and Sons
- Year
- 2006
- Tongue
- German
- Weight
- 109 KB
- Volume
- 89
- Category
- Article
- ISSN
- 0018-019X
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✦ Synopsis
Abstract
Discrepancies between chiroptical data from the literature and our determination of the structure of the title compounds (+)‐5 and (+)‐9a were resolved by an unambiguous assignment of their absolute configuration. Accordingly, the dextrorotatory cis‐3‐hydroxy esters have (3__R__,4__R__)‐ and the laevorotatory enantiomers (3__S__,4__S__)‐configuration. The final evidences were demonstrated on both enantiomers (+)‐ and (−)‐5 by biological reduction of 4 by bakers' yeast and stereoselective [Ru^II^(binap)]‐catalyzed hydrogenations of 4 (Scheme 2), by the application of the NMR Mosher method on (+)‐ and (−)‐5 (Scheme 3), as well as by the transformation of (+)‐5 into a common derivative and chiroptical correlation (Scheme 4).
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