Chemistry:Hemetsberger indole synthesis
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Short description: Chemical reaction
| Hemetsberger indole synthesis | |
|---|---|
| Named after | Helfried Hemetsberger |
| Reaction type | Ring forming reaction |
The Hemetsberger indole synthesis (also called the Hemetsberger–Knittel synthesis) is a chemical reaction that thermally decomposes a 3-aryl-2-azido-propenoic ester into an indole-2-carboxylic ester.[1][2]
Yields are typically above 70%. However, this is not a popular reaction, due to the lack of stability and difficulty in synthesizing the starting material.
Reaction mechanism
The mechanism is unknown. However, azirine[3] intermediates have been isolated. The mechanism is postulated to proceed via a nitrene intermediate.[4]
References
- ↑ Hemetsberger, H.; Knittel, D. (1972). "Synthese und Thermolyse von α-Azidoacrylestern". Monatshefte für Chemie 103: 194–204. doi:10.1007/BF00912944.
- ↑ Gribble, G. W. (2000). "Recent developments in indole ring synthesis-methodology and applications". J. Chem. Soc., Perkin Trans. (7): 1045–1075. doi:10.1039/a909834h.
- ↑ Gilchrist, T. L. (2001). "Activated 2H-Azirines as Dienophiles and Electrophiles". Aldrichimica Acta 34 (2): 51. Archived from the original on 15 May 2013. https://web.archive.org/web/20130515054311/http://www.sigmaaldrich.com/content/dam/sigma-aldrich/docs/Aldrich/Acta/al_acta34_2.pdf.
- ↑ Knittel, D. (1985). "Verbesserte Synthese von α-Azidozimtsäure-estern und 2H-Azirinen". Synthesis 1985 (2): 186–188. doi:10.1055/s-1985-31149.
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