CO2 on a tightrope: stabilization, room-temperature decarboxylation, and sodium-induced carboxylate migration
A sterically shielded 3-substituted zwitterionic N,N-dimethylisotryptammonium carboxylate has been synthesized by consecutive chemoselective double alkylation of indole. The carboxylate undergoes a quantitative and unusually facile decarboxylation in dimethyl sulfoxide (DMSO) or dimethyl formamide (...
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| Main Authors: | , , |
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| Format: | Article (Journal) Chapter/Article |
| Language: | English |
| Published: |
September 20, 2012
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| In: | Year: 2012, Volume: 18, Issue: 44, Pages: 14174-14185 |
| DOI: | 10.1002/chem.201202298 |
| Online Access: | Verlag, Volltext: http://dx.doi.org/10.1002/chem.201202298 Verlag, Volltext: https://onlinelibrary.wiley.com/doi/abs/10.1002/chem.201202298 
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| Author Notes: | Achim Häußermann, Frank Rominger, and Bernd F. Straub |
| Summary: | A sterically shielded 3-substituted zwitterionic N,N-dimethylisotryptammonium carboxylate has been synthesized by consecutive chemoselective double alkylation of indole. The carboxylate undergoes a quantitative and unusually facile decarboxylation in dimethyl sulfoxide (DMSO) or dimethyl formamide (DMF) at room temperature. The breaking of a nearly equidistant hydrogen bond by solvent molecules initiates heterolytic CC cleavage. The decarboxylation rate decreases with increasing CO2 partial pressure, proving the competitiveness of protonation and re-carboxylation of the carbanionic intermediate. Corresponding spiro compounds containing silylene and stannylene moieties show high thermal stability. Addition of an excess of methyllithium to the sodium salt triggers a reaction sequence comprising a deprotonation, carboxylate transfer, and nucleophilic trapping of the rearranged carboxylate by another equivalent of methyllithium. Hydrolytic work-up of the geminal diolate leads to an acetyl product. The role of the sodium counterion and the mechanism of the rearrangement have been unraveled by deuteration experiments. |
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| Item Description: | Gesehen am 24.04.2018 - Im Titel ist die Zahl "2" tiefergestellt |
| Physical Description: | Online Resource |
| DOI: | 10.1002/chem.201202298 |