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 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

Enantioselective Functionalization of Prochiral Cyclobutanones and Cyclobutenones

Synlett ◽  
2021 ◽  
Author(s):  
Memg Wang ◽  
Changxu Zhong ◽  
Ping Lu
Keyword(s):  
Asymmetric Synthesis ◽  
Membered Ring ◽  
Enantioselective Synthesis ◽  
Ring Compounds ◽  
Recent Advances ◽  
Cyclobutane Derivatives

Enantioselective synthesis of cyclobutane derivatives is still a challenging topic in asymmetric synthesis. [2+2]-Cycloaddition and skeleton rearrangement are two primary strategies to this end. Recently, functionalization of cyclobutanones and cyclobutenones, which are readily available via [2+2]-cycloadditions as prochiral substrates, has emerged as a powerful tool to access versatile four-membered ring compounds. Herein, we summarize some recent advances in these areas from our and other groups.

scholarly journals Rhodium-catalyzed asymmetric synthesis of silicon-stereogenic silicon-bridged arylpyridinones

2016 ◽  
Vol 7 (2) ◽  
pp. 1205-1211 ◽  
Author(s):  
Ryo Shintani ◽  
Ryo Takano ◽  
Kyoko Nozaki
Keyword(s):  
Asymmetric Synthesis ◽  
Enantioselective Synthesis ◽  
Catalytic Cycle

A rhodium-catalyzed regio- and enantioselective synthesis of silicon-stereogenic silicon-bridged arylpyridinones was developed. A reasonable catalytic cycle was also experimentally established.

One-Step Homologation for the Catalytic Asymmetric Synthesis of Deoxypropionates

2016 ◽  
Vol 23 (1) ◽  
pp. 149-156 ◽  
Author(s):  
Shiqing Xu ◽  
Haijun Li ◽  
Masato Komiyama ◽  
Akimichi Oda ◽  
Ei-ichi Negishi
Keyword(s):  
Asymmetric Synthesis ◽  
Catalytic Asymmetric Synthesis ◽  
One Step ◽  
Catalytic Asymmetric
Sign in / Sign up

Export Citation Format

Share Document