Efficient Synthesis of γ-Oxo- and γ-Hydroxy-α-amino Acids

Merla, Beatrix; Grumbach, Hans‐Joachim; Risch, Nikolaus

doi:10.1055/s-1998-2203

Cited by 11 publications

(12 citation statements)

References 9 publications

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“…A solution of di-(piperidin-1-yl) ethyl acetate [2] (2 mmol) in anhydrous CH 2 Cl 2 (3 mL) was cooled to 0 °C. Acetyl chloride (0.14 mL, 2 mmol) was added in one portion to generate the iminium salt 2b.…”

Section: Methods Bmentioning

confidence: 99%

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Aminoalkylation of cyclic and acyclic alkyl vinyl ethers

Merla

Risch

1999

J. prakt. Chem.

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The aminoalkylation of carbonyl compounds with ternary iminium salts is of general interest [1 -9]. Recently, we have disclosed that the aminoalkylation of ketones, enamines, imines (derivatives of aldehydes, cyclic or acyclic ketones) and aromatic compounds provides the corresponding Mannich bases in excellent yields and diastereoselectivities [1, 2, 8 -11]. By contrast, only a few other types of nucleophiles have been treated with ternary iminium salts containing alkyl, aryl and carboxylate groups, presumably because of the difficult preparation and handling of these compounds [12 -14]. Aminoalkylation of Cyclic and Acyclic Alkyl Vinyl EthersBeatrix Merla and Nikolaus Risch* Paderborn, Universität-GH, Fachbereich für Chemie und Chemietechnik Received March, 8th, 1999, respectively May 4th, 1999 Keywords: Mannich bases, Synthetic methods, Aminoalkylation, Vinyl ethers, Iminium salts Böhme and Wagner have already described the aminomethylation of the acyclic alkyl vinyl ethers (1a,b) with preformed methylene iminium salts (2a) (R = H and X = Cl) [15]. Only in those cases where the dehydrohalogenation is impossible (e.g. 1b : R 1 = H, R 2 = Me), were they able to isolate the α-halogenated ether 3 (Scheme 1).Katritzky et al. reported that the ethyl vinyl ether 1a can be aminoalkylated by 1-(α-aminoalkyl)benzotriazoles 5 (R = H, Ph) by heating (120 °C) to give quantitatively a mixture of the benzotriazol-1-yl (6) and -2-yl (7) adducts (R = Ph, NR' 2 = morpholine: 6 : 7 = 1 : 1, syn-6 : anti -6 = 1 : 1, syn-7 : anti-7 = 1 : 1) [16] (Scheme 2). These compounds are easily converted into the 1,3-amino ethers by treatment with alkyl magnesium bromide or lithium aluminium hydride [16].Abstract. The aminoalkylation of cyclic and acyclic alkyl vinyl ethers from inexpensive starting materials yields Mannich bases 4 and 10. Preformed and in situ generated iminium salts are used under mild reaction conditions. In some cases it is possible to isolate the α-halogenated 1,3-amino ethers 3 which have so far only ever been assumed to exist. Furthermore, the preparation of the already known 1-benzotriazolyl-3-aminoalkyl ethers 6 and 9 using this methodology is also successful.

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Section: Methods Bmentioning

confidence: 99%

“…The crude products 4b and 10b, respectively, were isolated as described above. The residue also contained 1-acetylpiperidine [2]. The product was purified by column chromatography (silica gel, CH 2 Cl 2 : MeOH = 98 : 2).…”

Section: Methods Bmentioning

confidence: 99%

Aminoalkylation of cyclic and acyclic alkyl vinyl ethers

Merla

Risch

1999

J. prakt. Chem.

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“…The initial quantities and possible variations are mentioned in the experimental part of the compound concerned. -2-yl-3,4,5,6,7,9-hexahydro-2H-xanthene-1,8- [45] 1,2,3,5,6,7,9,10,11,13,14,15-Decahydroacridino[4,3-b …”

Section: General Procedures For the Preparation Of Xanthene Derivativementioning

confidence: 99%

Synthesis of Novel Functionalized Bi- and Oligopyridines

Sielemann¹,

Keuper²,

Risch³

2000

Eur. J. Org. Chem.

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“…[10] In the course of our studies on modern variants of the Mannich reaction we have disclosed highly diastereoselective methods for the aminoalkylation of activated carbonyl compounds, for example, enamines or imines, with various ternary iminium salts. [11] This strategy has been applied successfully to the direct aminoalkylation of ketones, [12] α-branched aldehydes, [13] electron-rich aromatic compounds [14] and vinylogous nucleophiles. [15] Some examples of Mannich-type reactions involving phosphanes, phosphinates, phosphorus acids and phosphonates have previously been reported in the literature, but the reaction products are relatively simple and the reaction procedure cannot be employed with a variety of aldehydes and amines.…”

Section: Introductionmentioning

confidence: 99%

An Efficient Synthesis of Novel α‐Aminophosphonates Based on a Mannich‐Type Reaction

Risch¹,

Piper²,

Winter³

et al. 2005

Eur J Org Chem

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Phosphonate‐substituted iminium salt 2 was used in Mannich reactions with various nucleophiles to obtain novel α‐aminophosphonates. This straightforward and efficient methodology has a broad scope and provides highly functionalized Mannich bases (4 and 8). Furthermore, vinylic, aromatic and homoallylic α‐aminophosphonates (5, 10 and 12) were synthesized in good yields. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

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Efficient Synthesis of γ-Oxo- and γ-Hydroxy-α-amino Acids

Cited by 11 publications

References 9 publications

Aminoalkylation of cyclic and acyclic alkyl vinyl ethers

Aminoalkylation of cyclic and acyclic alkyl vinyl ethers

Synthesis of Novel Functionalized Bi- and Oligopyridines

An Efficient Synthesis of Novel α‐Aminophosphonates Based on a Mannich‐Type Reaction

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