Highly Enantioselective Synthesis of 2,6-Disubstituted and 2,2,6-Trisubstituted Dihydropyrones:  A One-Step Synthesis of (R)-(+)-Hepialone and Its Analogues

2005 ◽  
Vol 70 (21) ◽  
pp. 8533-8537 ◽  
Author(s):  
Weiqing Yang ◽  
Deju Shang ◽  
Yanling Liu ◽  
Ying Du ◽  
Xiaoming Feng
Keyword(s):  
Enantioselective Synthesis ◽  
One Step

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

Palladium(ii)-catalyzed asymmetric C–H carbonylation to diverse isoquinoline derivatives bearing all-carbon quaternary stereocenters

2020 ◽  
Vol 56 (78) ◽  
pp. 11605-11608
Author(s):  
Yan Li ◽  
Xiu-Fen Cheng ◽  
Fan Fei ◽  
Tian-Rui Wu ◽  
Kang-Jie Bian ◽  
...  
Keyword(s):  
Late Stage ◽  
Enantioselective Synthesis ◽  
One Step ◽  
Quaternary Stereocenters ◽  
Quaternary Stereocenter ◽  
Isoquinoline Derivatives

Enantioselective synthesis of isoquinoline derivatives bearing an all-carbon quaternary stereocenter in one step via asymmetric Pd(ii)-catalyzed C–H activation and multiple late-stage derivatizations.

One-step enantioselective synthesis of (4S)-isosclerone through biotranformation of juglone by an endophytic fungus

2013 ◽  
Vol 54 (10) ◽  
pp. 1189-1191 ◽  
Author(s):  
Soizic Prado ◽  
Didier Buisson ◽  
Idrissa Ndoye ◽  
Marine Vallet ◽  
Bastien Nay
Keyword(s):  
Endophytic Fungus ◽  
Enantioselective Synthesis ◽  
One Step

Asymmetric synthesis of functionalized pyrrolizidines by an organocatalytic and pot-economy strategy

RSC Advances ◽  
2016 ◽  
Vol 6 (10) ◽  
pp. 8243-8247 ◽  
Author(s):  
Chia-Hsin Lin ◽  
Bor-Cherng Hong ◽  
Gene-Hsiang Lee
Keyword(s):  
Asymmetric Synthesis ◽  
Enantioselective Synthesis ◽  
Oxidative Esterification ◽  
One Step

An enantioselective synthesis of indolizidines was achieved with a one-step purification by sequential asymmetric Michael–oxidative esterification–Michael–reduction–reductive Mannich–amidation reactions.

scholarly journals Practical highly enantioselective synthesis of (R)- and (S)-(E)-4-hydroxynon-2-enal.

2009 ◽  
Vol 56 (1) ◽  
Author(s):  
Marek Komisarski ◽  
Zuzanna Kaczmarska ◽  
Jarosław T Kuśmierek
Keyword(s):  
Optical Purity ◽  
Enantioselective Synthesis ◽  
The Other ◽  
Metathesis Reaction ◽  
2Nd Generation ◽  
Cross Metathesis ◽  
Cell Components ◽  
One Step ◽  
The Individual ◽  
Cell Cycle Signaling

Oxidative stress enhances lipid peroxidation (LPO) implicated in cancer promotion and progression. (E)-4-Hydroxynon-2-enal 1 (trans-4-hydroxy-2-nonenal, HNE) is one of the most abundant products of LPO. Reactions of HNE with DNA and proteins are responsible for its mutagenic and toxic effects. On the other hand, HNE is regarded as a key molecule in stress mediated cell cycle signaling. LPO generates racemic HNE (rac-1); however, it is expected that the individual enantiomers will behave differently in their interactions with cell components. The study of HNE stereochemistry in its chemical and biochemical interactions is hindered by the lack of expedient methods for preparation of pure enantiomers. This study presents one step synthesis of HNE in a cross-metathesis reaction between the commercially available oct-1-en-3-ol and acrolein in the presence of 2nd generation Grubbs catalyst. The use in the metathesis reaction of enantiomers of oct-1-en-3-ol obtained via Candida antarctica lipase resolution of the racemate allowed us to prepare of 4-(R)- and 4-(S)-enantiomers of HNE (R-1 and S-1, respectively) with excellent optical purity (97.5 and 98.4% ee, respectively) and good chemical yields (70%).

ChemInform Abstract: Organocatalytically Generated Donor-Acceptor Cyclopropanes in Domino Reactions. One-Step Enantioselective Synthesis of Pyrrolo[1,2-a]quinolines.

ChemInform ◽  
2016 ◽  
Vol 47 (31) ◽  
Author(s):  
Eduardo Sanchez-Diez ◽  
Diana L. Vesga ◽  
Efraim Reyes ◽  
Uxue Uria ◽  
Luisa Carrillo ◽  
...  
Keyword(s):  
Enantioselective Synthesis ◽  
Domino Reactions ◽  
Donor Acceptor ◽  
One Step

scholarly journals Organocatalytically Generated Donor–Acceptor Cyclopropanes in Domino Reactions. One-Step Enantioselective Synthesis of Pyrrolo[1,2-a]quinolines

2016 ◽  
Vol 18 (6) ◽  
pp. 1270-1273 ◽  
Author(s):  
Eduardo Sanchez-Diez ◽  
Diana L. Vesga ◽  
Efraim Reyes ◽  
Uxue Uria ◽  
Luisa Carrillo ◽  
...  
Keyword(s):  
Enantioselective Synthesis ◽  
Domino Reactions ◽  
Donor Acceptor ◽  
One Step

An Interactive Minicomputer Program for the Indexing and Simulation of Electron Diffraction Patterns

1976 ◽  
Vol 34 ◽  
pp. 542-543
Author(s):  
R.P. Goehner ◽  
W.T. Hatfield ◽  
Prakash Rao
Keyword(s):  
Electron Diffraction ◽  
Real Time ◽  
Pattern Analysis ◽  
Flow Diagram ◽  
Hard Copy ◽  
Time Analysis ◽  
Real Time Analysis ◽  
Transmission Electron ◽  
One Step ◽  
Diffraction Patterns

Computer programs are now available in various laboratories for the indexing and simulation of transmission electron diffraction patterns. Although these programs address themselves to the solution of various aspects of the indexing and simulation process, the ultimate goal is to perform real time diffraction pattern analysis directly off of the imaging screen of the transmission electron microscope. The program to be described in this paper represents one step prior to real time analysis. It involves the combination of two programs, described in an earlier paper(l), into a single program for use on an interactive basis with a minicomputer. In our case, the minicomputer is an INTERDATA 70 equipped with a Tektronix 4010-1 graphical display terminal and hard copy unit.A simplified flow diagram of the combined program, written in Fortran IV, is shown in Figure 1. It consists of two programs INDEX and TEDP which index and simulate electron diffraction patterns respectively. The user has the option of choosing either the indexing or simulating aspects of the combined program.

Catalytic enantioselective synthesis of indolizino[8,7-b]indole alkaloid derivatives based on the tandem reaction of tertiary enamides

2021 ◽  
Author(s):  
Xin-Ming Xu ◽  
Ming Xie ◽  
Jiazhu Li ◽  
Mei-Xiang Wang
Keyword(s):  
Indole Alkaloid ◽  
Enantioselective Synthesis ◽  
High Yield ◽  
Tandem Reaction ◽  
Indole Derivatives

An exquisite Pybox/Cu(OTf)2-catalyzed asymmetric tandem reaction of tertiary enamides was developed, which enabled the expeditious synthesis of indolizino[8,7-b]indole derivatives in high yield, excellent enantioselectivity and diastereoselectivity.

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