Stereo-regulated synthesis of peptides containing a β-trifluoromethyl-β-amino acid
摘要:
For the chemical conversions of a beta-trifluoromethyl-beta-amino acid ((S)-4,4,4-trifluoro-3-aminobutyric acid, 1), such as the N-terminus protection with benzyloxycarbonyl or tert-butoxycarbonyl group, the C-terminus protection with benzyl or tert-butyl group, and peptide elongation at the both termini, highly practical protocols were established. Through these conversions, the stereochemistry of 1 and/or its condensation counterpart was maintained. Because the protocols developed here are indispensable for the application of 1 in peptide engineering, they would expand the utility of 1 and its derivatives. (C) 2013 Elsevier Ltd. All rights reserved.
A practical method to access enantiopure β-perfluoroalkyl-β-amino acids: diastereoselective reduction of cyclic enamino-esters
摘要:
A highly practical method to access enantiopure beta-perfluoroalkyl-beta-amino acids was developed, which Could be conducted Without any expensive reagent, special apparatus/technique, nor tedious chromatographic separation. The condensation of methyl 4,4,4-trifluoro-3-oxobutanoate with (S)-2-amino-2-phenylethanol, followed by an intramoleculer transesterification, gave an enamino-ester with a seven-membered ring structure. The hydride reduction of the cyclic enamino-ester proceeded with excellent diastereoselectivity (dr = 95:5-97:3) to give the corresponding cyclic amino-ester. The major isomer of the cyclic amino-ester was readily separated from the minor one and successfully converted into (S)-3-amino-4,4,4-trifluorobutanoic acid (five steps, 38% overall yield, >99% ee). Concerning the key step of this synthesis, the same strategy was applicable to another substrate: the asymmetric hydride reduction of a cyclic enamino-ester with a pentafluoroethyl group also proceeded in excellent diastereoselectivity (dr = 96:4). (C) 2009 Elsevier Ltd. All rights reserved.
Asymmetric Mannich reaction between (S)-N-(tert-butanesulfinyl)-3,3,3-trifluoroacetaldimine and malonic acid derivatives. Stereodivergent synthesis of (R)- and (S)-3-amino-4,4,4-trifluorobutanoic acids
作者:Norio Shibata、Takayuki Nishimine、Naoyuki Shibata、Etsuko Tokunaga、Kosuke Kawada、Takumi Kagawa、José Luis Aceña、Alexander E. Sorochinsky、Vadim A. Soloshonok
DOI:10.1039/c3ob42425a
日期:——
diastereoselective Mannich additions of malonic acidderivatives to (SS)-N-(tert-butanesulfinyl)-3,3,3-trifluoroacetaldimine. In the presence of catalytic amounts of inorganic bases, n-BuLi or DMAP, the reaction gives the corresponding (R,SS)-β-aminomalonates in good yield and with diastereoselectivity up to 9/1 dr. In contrast, phosphazene bases favour the formation of the (S,SS)-diastereomer with selectivities
Organic base-catalyzed stereodivergent synthesis of (R)- and (S)-3-amino-4,4,4-trifluorobutanoic acids
作者:Norio Shibata、Takayuki Nishimine、Naoyuki Shibata、Etsuko Tokunaga、Kosuke Kawada、Takumi Kagawa、Alexander E. Sorochinsky、Vadim A. Soloshonok
DOI:10.1039/c2cc30627a
日期:——
base-catalyzed reaction of (S)-N-tert-butanesulfinyl (3,3,3)-trifluoroacetaldimine with dialkyl malonates was found to be effective for synthesis of both (S,S(S)) and (R,S(S)) beta-aminomalonates in high yield with good to excellent diastereoselectivity (76-98% de). The products of this Mannich reaction provide direct access to beta-trifluoromethyl-beta-alanine of either (R) or (S) absolute configuration
Operationally convenient asymmetric synthesis of (S)- and (R)-3-amino-4,4,4-trifluorobutanoic acid
作者:Vadim A. Soloshonok、Hironari Ohkura、Manabu Yasumoto
DOI:10.1016/j.jfluchem.2006.04.004
日期:2006.7
An asymmetric synthesis of (S)- and (R)-3-amino-4,4,4-trifluorobutanoic acidvia DBU-catalyzed asymmetric 1,3-proton shift transfer reaction of (Z)-3-[(R)-1-phenylethylamino]-4,4,4-trifluoro-N-[(R)-1-phenylethyl]but-2-enamide has been developed. The intermediate Schiff base (S,R′)-9 was found to be relatively configurationally stable under the highly basic reaction conditions allowing preparation of
Kukhar', V. K.; Soloshonok, V. A.; Shvyadas, V. K., Russian Journal of Bioorganic Chemistry, 1993, vol. 19, # 4, p. 233 - 235
作者:Kukhar', V. K.、Soloshonok, V. A.、Shvyadas, V. K.、Kotik, N. V.、Galaev, I. Yu、et al.
DOI:——
日期:——
Biocatalytic resolution of β-fluoroalkyl-β-amino acids
作者:Vadim A. Soloshonok、Alexander G. Kirilenko、Nataly A. Fokina、Irine P. Shishkina、Sergey V. Galushko、Valery P. Kukhar、Vytas K. Švedas、Elena V. Kozlova
DOI:10.1016/0957-4166(94)80063-4
日期:1994.6
N-Phenylacetyl derivatives of beta-fluoroalkyl-beta-alanines 6 were synthesized and biocatalytically resolved to the corresponding enantiopure beta-amino acids 7, 9 with the aid of penicillin acylase (EC 3.5.1.11) from Escherichia coli. In substrates 6 the enantioselectivity of the biocatalytic process was practically uninfluenced by the nature of the fluoroalkyl chain. Thus, beta-fluoroalkyl-beta-alanines 7, 9 bearing short (R = CF3, CHF2) or long [C3F7, H(CF2)(4)] chains were prepared in high enantiomeric purity. The (R)-enantiomer was the fast-reacting enantiomer in all cases.