التفاصيل البيبلوغرافية
| العنوان: |
Asymmetric 1,4‐Addition Reactions Catalyzed by N‐Terminal Thiourea‐Modified Helical l‐Leu Peptide with Cyclic Amino Acids. |
| المؤلفون: |
Sato, Kazuki, Umeno, Tomohiro, Ueda, Atsushi, Kato, Takuma, Doi, Mitsunobu, Tanaka, Masakazu |
| المصدر: |
Chemistry - A European Journal; 8/2/2021, Vol. 27 Issue 43, p11216-11220, 5p |
| مصطلحات موضوعية: |
AMINO acids, ASYMMETRIC synthesis, PHENYL group, HELICAL structure, MALONATES, N-terminal residues, DIALKYLZINC, ADDITION reactions |
| مستخلص: |
N‐terminal thiourea‐modified l‐Leu‐based peptide {(3,5‐diCF3Ph)NHC(=S)‐(l‐Leu‐l‐Leu‐Ac5c)2‐OMe} with five‐membered ring α,α‐disubstituted α‐amino acids (Ac5c) catalyzed a highly enantioselective 1,4‐addition reaction between β‐nitrostyrene and dimethyl malonate. The enantioselective reaction required only 0.5 mol % chiral peptide‐catalyst in the presence of iPr2EtN (2.5 equiv.), and gave a 1,4‐adduct with 93 % ee of an 85 % yield. As Michael acceptors, various β‐nitrostyrene derivatives such as methyl, p‐fluoro, p‐bromo, and p‐methoxy substituents on the phenyl group, 2‐furyl, 2‐thiophenyl, and naphthyl β‐nitroethylenes could be applied. Furthermore, various alkyl malonates and cyclic β‐keto‐esters could be used as Michael donors. It became clear that the length of the peptide chain, a right‐handed helical structure, amide N−Hs, and the N‐terminal thiourea moiety play crucial roles in asymmetric induction. [ABSTRACT FROM AUTHOR] |
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| قاعدة البيانات: |
Complementary Index |
