Belokon, Yuri N., Kochetkov, Konstantin A., Churkina, Tatiana D. , Ikonnikov, Nikolai S., Chesnokov, Alexey A., Larionov, Oleg V., Singh, Ishwar, Parmar, Virinder S., Vyskocil, Stepan and Kagan, Henri B. (2000) Asymmetric PTC C-alkylation catalyzed by chiral derivatives of tartaric acid and aminophenols. Synthesis of (R)- and (S)-alpha-methyl amino acids. Journal of Organic Chemistry, 65 (21). pp. 7041-7048. ISSN 0022-3263
Full content URL: http://dx.doi.org/10.1021/jo000719p
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| Item Type: | Article |
|---|---|
| Item Status: | Live Archive |
Abstract
A new type of efficient chiral catalyst has been elaborated for asymmetric C-alkylation of CH acids under PTC conditions. Sodium alkoxides formed from chiral derivatives of tartaric acid and aminophenols (TADDOL's 2a-e and NOBLN's 3a-h) can be used as chiral catalysts in the enantioselective alkylation, as exemplified by the reaction of Schiff's bases Pa-e derived from alanine esters and benzaldehydes with active alkyl halides. Acid-catalyzed hydrolysis of the products formed in the reaction afforded (R)-alpha -methylphenylalanine, (R)-alpha -naphthylmethylalanine, and (R)alpha -allylalanine in 61-93% yields and with ee 69-93%. The procedure could be successfully scaled up to 6 g of substrate 1b. When (S,S)-TADDOL or (R)-NOBIN are used, the (S)-amino acids are formed. A mechanism rationalizing the observed features of the reaction has been suggested.
| Additional Information: | Publication Date (Web): September 22, 2000 |
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| Keywords: | Alkylation |
| Subjects: | B Subjects allied to Medicine > B200 Pharmacology, Toxicology and Pharmacy |
| Divisions: | College of Science > School of Pharmacy |
| ID Code: | 11315 |
| Deposited On: | 24 Jul 2013 09:40 |
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