Polymer-Supported Cinchona Alkaloid-Derived Ammonium Salts as Recoverable Phase-Transfer Catalysts for the Asymmetric Synthesis of α-Amino Acids
Abstract
:Introduction
Results and Discussion
Entry | Catalyst | Base | Solvent | T (ºC) | t (h) | Yielda (%) | eeb (%) |
---|---|---|---|---|---|---|---|
1 | 2a | 25% NaOH | PhMe | 25 | 4 | 90 | 66 |
2 | 2a | 25% NaOH | PhMe | 0 | 17 | 90 | 90 |
3 | 2a | 25% KOH | PhMe:CHCl3 | -20 | 10 | 46 | 76 |
4 | 2a | 50% KOH | PhMe:CHCl3 | -40 | 9 | 56 | 85 |
5 | 2b | 25% NaOH | PhMe | 25 | 10 | 62 | 34 |
6 | 2b | 25% NaOH | PhMe | 0 | 140 | 23 | 50 |
7 | 2c | 25% NaOH | PhMe | 25 | 8 | 76 | 18 |
8 | 2c | 25% NaOH | PhMe | 0 | 96 | 81 | 20 |
9 | 9 | 25% NaOH | PhMe | 0 | 160 | 33 | 2 |
10 | 10a | 25% NaOH | PhMe | 25 | 1 | 96 | 44 |
11 | 10a | 25% NaOH | PhMe | 0 | 10 | 59 | 70 |
12 | 10a | 50% KOH | PhMe:CHCl3 | -20 | 18 | 71 | 69 |
13 | 10b | 25% NaOH | PhMe | 0 | 120 | 7 | 2 |
14 | 11 | 25% NaOH | PhMe | 25 | 4 | 76 | 62 |
15 | 11 | 25% NaOH | PhMe | 0 | 10 | 71 | 56 |
16 | 12 | 25% NaOH | PhMe | 25 | 12 | 78 | 56 |
17 | 12 | 25% NaOH | PhMe | 0 | 120 | 63 | 54 |
18 | 13a | 25% NaOH | PhMe | 25 | 10 | 75 | 63 |
19 | 13a | 25% NaOH | PhMe | 0 | 20 | 91 | 64 |
20 | 13a | 50% KOH | PhMe:CHCl3 | -20 | 15 | 90 | 68 |
21 | 13b | 25% NaOH | PhMe | 0 | 60 | 28 | 8 |
22 | 16 | 25% NaOH | PhMe | 25 | 2 | 92 | 59 |
23 | 16 | 25% NaOH | PhMe | 0 | 32 | 94 | 70 |
24 | 16 | 50% KOH | PhMe:CHCl3 | -20 | 3 | 86 | 74 |
25 | 18 | 25% NaOH | PhMe | 25 | 1 | 96 | 44 |
26 | 18 | 25% NaOH | PhMe | 0 | 170 | 49 | 70 |
27 | 18 | 50% KOH | PhMe:CHCl3 | -20 | 13 | 74 | 71 |
Conclusions
Acknowledgments
Experimental
General
General procedure for the preparation of the polymeric ammonium salts 2 and 9-13.
Polymeric ammonium salt 2a
Polymeric ammonium salt 2b
Polymeric ammonium salt 2c
Polymeric ammonium salt 9
Polymeric ammonium salt 10a
Polymeric ammonium salt 10b
Polymeric ammonium salt 11
Polymeric ammonium salt 12
Polymeric ammonium salt 13a
Polymeric ammonium salt 13b
Preparation of polymeric ammonium salt 16
Preparation of co-polymeric ammonium salt 18 [27]
General procedure for the benzylation of 19 using the polymeric ammonium salts as PTC catalysts: Preparation of isopropyl 2-diphenylmethylenamino-3-phenylpropanoate (20).
References and Notes
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Chinchilla, R.; Mazón, P.; Nájera, C. Polymer-Supported Cinchona Alkaloid-Derived Ammonium Salts as Recoverable Phase-Transfer Catalysts for the Asymmetric Synthesis of α-Amino Acids. Molecules 2004, 9, 349-364. https://doi.org/10.3390/90500349
Chinchilla R, Mazón P, Nájera C. Polymer-Supported Cinchona Alkaloid-Derived Ammonium Salts as Recoverable Phase-Transfer Catalysts for the Asymmetric Synthesis of α-Amino Acids. Molecules. 2004; 9(5):349-364. https://doi.org/10.3390/90500349
Chicago/Turabian StyleChinchilla, Rafael, Patricia Mazón, and Carmen Nájera. 2004. "Polymer-Supported Cinchona Alkaloid-Derived Ammonium Salts as Recoverable Phase-Transfer Catalysts for the Asymmetric Synthesis of α-Amino Acids" Molecules 9, no. 5: 349-364. https://doi.org/10.3390/90500349