The readily available 2,4,6-tri(terf-buty1)-and 2,6-di(tert-butyl)-4-methoxyphenol esters 2 of a-nitrocyclopropanecarboxylic acid undergo ring opening with C-, N-, 0-, and S-nucleophiles (cyanide, malonate, azide, anilines, alkoxides, phenoxides, thiolates) in DMF or alcohol solvents (80-95 % yield)
Nucleophile Ringöffnung von 1-Nitro-1-cyclopropancarbonsäure-arylestern mit sterisch geschützter, aber elektronisch wirksamer Carbonyl- und Nitrogruppe. Ein neues Prinzip der Aminosäuresynthese
✍ Scribed by Vettiger, Thomas ;Seebach, Dieter
- Book ID
- 102902254
- Publisher
- John Wiley and Sons
- Year
- 1990
- Tongue
- English
- Weight
- 761 KB
- Volume
- 1990
- Category
- Article
- ISSN
- 0947-3440
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✦ Synopsis
Nucleophilic Ring Opening of Aryl 1‐Nitro‐1‐cyclopropanecarboxylate with Sterically Protected, but Electronically Effective Carbonyl and Nitro Group. A New Principle of Amino Acid Synthesis
The readily available [2,6‐di‐(tert‐butyl)‐4‐methoxyphenyl] 1‐nitro‐1‐cyclopropanecarboxylate (4) is ring‐opened by nucleophilic attack of the amino groups of (S)‐α‐amino acid esters (products 20–26). Reduction of the nitro group gives rise to derivatives 27–30 of 2,4‐diaminobutanoic acid which are connected with a second amino acid through the nitrogen in position 4 (2‐substituted 6‐amino‐3‐azaheptanedioic acids). In two cases, these were converted into enantiomerically and diastereomerically pure Freidinger's γ‐lactam dipeptides (31, 32), which have previously been shown to mimic a peptide β‐turn.
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