- Stereoselective Synthesis of (E)-α,β-dehydroamino acid esters
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Dehydroamino acid (Dhaa) is recognized as a useful tool or substrate for amino acid and peptide research. Although the stereoselective synthesis of the thermodynamically more stable Z-Dhaa has been well examined and established, the stereoselective synthesis of E-Dhaa has still remained to be a challenging synthetic task. In this paper, a stereoselective synthesis of E-Dhaa esters using a new (α-diphenylphosphono)glycine is described. The characteristic aspects of the new method are summarized as follows: (i) metal additives play an important role in the promotion of E-stereoselectivities. (ii) the use of NaI was effected for the synthesis of E-Dhaas bearing an aryl substituent and an amino functionality, (iii) MgBr2·OEt2 and ZnCl 2 contributed to improve the E-stereoselective synthesis of E-Dhaas bearing an alkyl substituent and an oxygen functionality, (iv) various protecting and functional groups were compatible under the reaction conditions, and (v) N-Cbz, Boc, and acyl-α-(diphenylphosphono)glycines were served for the stereoselective olefination reaction to provide the corresponding E-Dhaas. A variety of (E)-dehydroamino acid esters were stereoselectively synthesized by using (diphenylphosphono)glycinate. The stereoselectivity was influenced by metal additives. Various (E)-dehydroamino acid esters were prepared by the condensation reaction of the new phosphonates with easily available aldehydes by choosing the appropriate reaction conditions.
- Yasuno, Yoko,Hamada, Makoto,Yamada, Takeshi,Shinada, Tetsuro,Ohfune, Yasufumi
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supporting information
p. 1884 - 1888
(2013/05/08)
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- Synthesis of the central tryptophan-leucine residue of celogentin C
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The synthesis of the central tryptophan residue of celogentin C is described featuring a Pd-catalyzed imine/enamine Heck-type reaction, a Pd-catalyzed Suzuki coupling, and an asymmetric Rh-catalyzed hydrogenation.
- Michaux, Julien,Retaillea, Pascal,Campagne, Jean-Marc
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scheme or table
p. 1532 - 1536
(2009/04/10)
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- Deconjugation of dehydroamino acids: Stereoselective synthesis of racemic (E)-vinylglycines
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(Chemical Equation Presented) A practical and general two-step synthesis of carbamate-protected (E)-vinylglycines from aliphatic aldehydes is reported. The key step involves the kinetic α-protonation of dianionic dienolates derived from dehydroamino acids
- Alexander, Paul A.,Marsden, Stephen P.,Munoz Subtil, Dulce M.,Reader, John C.
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p. 5433 - 5436
(2007/10/03)
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- Diastereoselective formation of (Z)-didehydroamino acid esters
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The rearrangement of (E)-didehydroamino acid derivatives to the corresponding Z-derivatives under acid or basic catalysis as well as under the influence of radicals has been investigated. The condensation of N-benzyloxycarbonyl or N-tert-butoxycarbonyl protected alkyl 2-amino-2-(dimethoxyphosphoryl)acetates with aldehydes or ketones in dichloromethane in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene furnishes (Z)-didehydroamino acid ester derivatives diastereoselectively in excellent yields and with high purity.
- Schmidt,Griesser,Leitenberger,Lieberknecht,Mangold,Meyer,Riedl
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p. 487 - 490
(2007/10/02)
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