Induction of Asymmetry by Amino Acids

Drauz, Karlheinz; Kleeman, Axel; Martens, Jürgen

doi:10.1002/anie.198205841

Cited by 96 publications

(10 citation statements)

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“…The transformation of 4a؊f into (R)-2-methylpyrrolidine, [23] (R)-2-ethylpyrrolidine, [24] (R)-2-propylpyrrolidine, [25] (S)-2-isopropylpyrrolidine, [26] (R)-2-butylpirrolidine, [27] and (R)-2-phenethylpyrrolidine, [28] isolated as tosylates, was carried out by removal of the N-benzyl moiety by hydrogenolysis over palladium on carbon and treatment with to- syl chloride. The enantiomeric purity of the corresponding pyrrolidines was measured by 19 F NMR spectroscopy of the MTPA derivatives and the configuration of the final products was determined by comparison of the sign of the optical rotation previously described.…”

mentioning

confidence: 99%

A Simple Stereoselective Synthesis of Enantiopure 2-Substituted Pyrrolidines and Piperidines from Chiral (R)-Phenylglycinol-Derived Bicyclic 1,3-Oxazolidines

Andrés

Herráiz-Sierra

Pedrosa³

et al. 2000

Eur. J. Org. Chem.

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Chiral, nonracemic 2-substituted pyrrolidines and piperidines were prepared in high ee and moderate to good chemical yields in three steps from (R)-phenylglycinol and γ-or δchloroketones. The key step of the synthesis was the stereo- IntroductionThe pyrrolidine and piperidine ring systems are present in many natural products and biologically important substances. [1] As a part of an ongoing project directed to this type of heterocycle, [2] we describe now a short route to enantiopure 2-substituted pyrrolidines and piperidines from the chiral perhydropyrrolo[2,1-b][1,3]oxazoles 3a؊f and perhydropyrido [2,1-b][1,3]oxazoles 3g؊i (bicyclic oxazolidines) derived from (R)-phenylglycinol. Both enantiomers of phenylglycinol have been used as chiral auxiliaries in monoand bicyclic oxazolidine-mediated diastereoselective synthesis. [3] Recently, the preparation of alkaloids, [4] amino acids, [5] piperidines, [6] and isoindoline derivatives [7] by using oxazolidines derived from phenylglycinol has been reported. In the same way, bicyclic oxazolidines prepared from phenylglycinols and dialdehydes have been demonstrated to be excellent starting materials in the synthesis of enantiopure morpholines, [8] pyrrolidines, [9] piperidines [10] or aminophosphonates; [11] chiral bicyclic lactams have also been successfully used in the preparation of both pyrrolidines [12] and piperidines. [13] The chiral bicyclic oxazolidines 3a؊i were prepared (Scheme 1) by condensation of (R)-(Ϫ)-phenylglycinol and the corresponding γ-or δ-chloroketones 2a؊i at room temp. in chloroform or toluene and triethylamine as solvents. It should be noted that it was necessary to work at high concentration (ca. 10 ) to ensure that the condensation finished in 24Ϫ120 h. [14] Chloroketone 2a was commercially available and 2b, [15] 2c, [16] 2d, [17] 2e, [15] 2f, [18] 2g, [19] 2h [20] and 2i [21] were easily prepared from 4-chlorobutanoyl chloride or 5-chloropentanoyl chloride by reaction with organometallic reagents. [22] The condensation was diastereoselective, leading to a mixture of epimers at the angular carbon of the bicyclic [a]

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confidence: 99%

A Simple Stereoselective Synthesis of Enantiopure 2-Substituted Pyrrolidines and Piperidines from Chiral (R)-Phenylglycinol-Derived Bicyclic 1,3-Oxazolidines

Andrés

Herráiz-Sierra

Pedrosa³

et al. 2000

Eur. J. Org. Chem.

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“…Seit einigen Jahren werden Prolin‐katalysierte Carbonylreaktionen sehr intensiv bearbeitet, nachdem sie über 40 Jahre fast unbeachtet geblieben waren 1. Obwohl Martens et al bereits 1982 in einem Aufsatz auf das riesige Potenzial dieser Reaktionen deutlich hinwiesen, fanden sie erst durch die Arbeiten von List, Barbas, MacMillan, Jørgensen und anderen die Beachtung, die ihnen zusteht 2. Nach heutigem Verständnis könnten Prolin‐katalysierte Carbonylreaktionen die präbiotische Bildung von Aldol‐ und Mannich‐Produkten und somit auch die stereoselektive Synthese von Kohlenhydraten erklären.…”

Section: Methodsunclassified

Dihydroxyaceton in Aminosäure‐katalysierten Mannich‐Reaktionen

Westermann

Neuhaus

2005

Angewandte Chemie

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“…The transformation of 4a؊f into (R)-2-methylpyrrolidine, [23] (R)-2-ethylpyrrolidine, [24] (R)-2-propylpyrrolidine, [25] (S)-2-isopropylpyrrolidine, [26] (R)-2-butylpirrolidine, [27] and (R)-2-phenethylpyrrolidine, [28] isolated as tosylates, was carried out by removal of the N-benzyl moiety by hydrogenolysis over palladium on carbon and treatment with to- de [b] Yield (%) [a] de [b] Yield (%) syl chloride. The enantiomeric purity of the corresponding pyrrolidines was measured by 19 F NMR spectroscopy of the MTPA derivatives and the configuration of the final products was determined by comparison of the sign of the optical rotation previously described.…”

Section: Introductionmentioning

confidence: 99%