Chiral Benzyllithium Compounds: High Configurative Stability of (R)- and (S)-1-Lithioindan-1-yl N,N-Diisopropylcarbamate and Unexpected Stereochemical Course of the Substitution Reactions
✍ Scribed by Christoph Derwing; Holger Frank; Dieter Hoppe
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 381 KB
- Volume
- 1999
- Category
- Article
- ISSN
- 1434-193X
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✦ Synopsis
The title compound, 6, was generated by stereospecific chlorides leads to partial racemization due to competing front face attack. Semiempirical calculations point to an increased deprotonation of the optically active carbamate 5 with secbutyllithium/TMEDA and proved to be configuratively degree of pyramidalization and to a higher barrier for planarization in the cyclic benzyllithium compound, both of completely stable in ethereal solution at -78 °C. Compared with open-chain analogs, the trend for stereoretentive which disfavor the rear face attack. substitution is enhanced. Even the reaction with trialkyltin [a] Organisch-Chemisches Institut der Westfälischen Wilhelms-Universität Münster, performed. [9] The results are collected in Table 1.
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The enantiomeric excesses could be determined (with the