Stereoselective Synthesis of Unsaturated and Functionalized l-NHBoc Amino Acids, Using Wittig Reaction under Mild Phase-Transfer Conditions

2012 ◽  
Vol 77 (17) ◽  
pp. 7579-7587 ◽  
Author(s):  
Emmanuelle Rémond ◽  
Jérôme Bayardon ◽  
Marie-Joëlle Ondel-Eymin ◽  
Sylvain Jugé
Keyword(s):  
Amino Acids ◽  
Wittig Reaction ◽  
Stereoselective Synthesis ◽  
Phase Transfer

The stereoselective synthesis of .alpha.-amino acids by phase-transfer catalysis

1989 ◽  
Vol 111 (6) ◽  
pp. 2353-2355 ◽  
Author(s):  
Martin J. O'Donnell ◽  
William D. Bennett ◽  
Shengde Wu
Keyword(s):  
Amino Acids ◽  
Phase Transfer Catalysis ◽  
Stereoselective Synthesis ◽  
Phase Transfer

scholarly journals Peculiarities of promiscuous l-threonine transaldolases for enantioselective synthesis of β-hydroxy-α-amino acids

2021 ◽  
Author(s):  
Shan Wang ◽  
Hai Deng
Keyword(s):  
Amino Acids ◽  
Organic Molecules ◽  
Stereoselective Synthesis ◽  
Enantioselective Synthesis ◽  
General Mechanism ◽  
Future Developments ◽  
Key Points ◽  
Biomaterial Science ◽  
One Step ◽  
Harsh Conditions

Abstract The introduction of β-hydroxy-α-amino acids (βHAAs) into organic molecules has received considerable attention as these molecules have often found widespread applications in bioorganic chemistry, medicinal chemistry and biomaterial science. Despite innovation of asymmetric synthesis of βHAAs, stereoselective synthesis to control the two chiral centres at Cα and Cβ positions is still challenging, with poor atomic economy and multi protection and deprotection steps. These syntheses are often operated under harsh conditions. Therefore, a biotransformation approach using biocatalysts is needed to selectively introduce these two chiral centres into structurally diverse molecules. Yet, there are few ways that enable one-step synthesis of βHAAs. One is to extend the substrate scope of the existing enzyme inventory. Threonine aldolases have been explored to produce βHAAs. However, the enzymes have poor controlled installation at Cβ position, often resulting in a mixture of diastereoisomers which are difficult to be separated. In this respect, l-threonine transaldolases (LTTAs) offer an excellent potential as the enzymes often provide controlled stereochemistry at Cα and Cβ positions. Another is to mine LTTA homologues and engineer the enzymes using directed evolution with the aim of finding engineered biocatalysts to accept broad substrates with enhanced conversion and stereoselectivity. Here, we review the development of LTTAs that incorporate various aldehyde acceptors to generate structurally diverse βHAAs and highlight areas for future developments. Key points • The general mechanism of the transaldolation reaction catalysed by LTTAs • Recent advances in LTTAs from different biosynthetic pathways • Applications of LTTAs as biocatalysts for production of βHAAs

scholarly journals Stereoselective Synthesis of Tetraalkyl Cyclobutene-1,2,3,4-tetracarboxylates. Synthesis of Tetraalkyl (Z,Z)-Buta-1,3-diene-1,2,3,4-tetracarboxylates

1999 ◽  
Vol 23 (8) ◽  
pp. 512-513
Author(s):  
Issa Yavari ◽  
Farahnaz Nourmohammadian
Keyword(s):  
Ring Opening ◽  
Wittig Reaction ◽  
Stereoselective Synthesis ◽  
Intramolecular Wittig Reaction ◽  
Ring Opening Reactions ◽  
Boiling Toluene

Tetraalkyl cyclobutene-1,2,3,4-tetracarboxylates, prepared by intramolecular Wittig reaction between a vinylphosphonium salt and diethyl 2-oxobutanedioate, undergo electrocyclic ring-opening reactions, in boiling toluene, to produce highly electron-deficient 1,3-dienes.

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