Highly diastereo- and enantioselective organocatalytic synthesis of trifluoromethylated erythritols based on the in situ generation of unstable trifluoroacetaldehyde

2021 ◽  
Author(s):  
Kazumasa Funabiki ◽  
Toshiya Gotoh ◽  
Ryunosuke Kani ◽  
Toshiyasu Inuzuka ◽  
Yasuhiro Kubota
Keyword(s):  
Trifluoromethyl Group ◽  
In Situ Generation

A highly diastereo- and enantioselective organocatalytic method to synthesise erythritols bearing a trifluoromethyl group has been investigated.

Recent advances in Minisci-type reactions and applications in organic synthesis

2020 ◽  
Vol 24 ◽  
Author(s):  
Wengui Wang ◽  
Shoufeng Wang
Keyword(s):  
Free Radical ◽  
Hydrogen Atom ◽  
Organic Synthesis ◽  
Radical Reactivity ◽  
Atom Loss ◽  
Radical Generation ◽  
In Situ Generation ◽  
Thermal Cleavage ◽  
Synthetic Chemist

Abstract:: Minisci-type reactions have become widely known as reactions that involve the addition of carbon-centered radicals to basic heteroarenes followed by formal hydrogen atom loss. While the originally developed protocols for radical generation remain in active use today, in recent years by a new array of radical generation strategies allow use of a wider variety of radical precursors that often operate under milder and more benign conditions. New transformations based on free radical reactivity are now available to a synthetic chemist looking to utilize a Minisci-type reaction. Radical-generation methods based on photoredox catalysis and electrochemistry, which utilize thermal cleavage or the in situ generation of reactive radical precursors, have become popular approaches. Our review will cover the remarkably literature that has appeared on this topic in recent 5 years, from 2015-01 to 2020-01, in an attempt to provide guidance to the synthetic chemist, on both the challenges that have been overcome and applications in organic synthesis.

scholarly journals A residue-free approach to water disinfection using catalytic in situ generation of reactive oxygen species

2021 ◽  
Author(s):  
Thomas Richards ◽  
Jonathan H. Harrhy ◽  
Richard J. Lewis ◽  
Alexander G. R. Howe ◽  
Grzegorz M. Suldecki ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Reactive Oxygen ◽  
Water Disinfection ◽  
Oxygen Species ◽  
In Situ Generation

In Situ Generation of Unstable Difluoromethylphosphonate-Containing Diazoalkanes and Their Use in [3 + 2] Cycloaddition Reactions with Vinyl Sulfones

2021 ◽  
Vol 23 (3) ◽  
pp. 1130-1134
Author(s):  
Haibo Mei ◽  
Li Wang ◽  
Romana Pajkert ◽  
Qian Wang ◽  
Jingcheng Xu ◽  
...  
Keyword(s):  
Cycloaddition Reactions ◽  
In Situ Generation

Experimental Investigation of Laser Sintering of Conductive Adhesive for Functional Prototypes Produced by Embedding Stereolithography

2014 ◽  
Vol 1038 ◽  
pp. 75-81
Author(s):  
Bernd Niese ◽  
Philipp Amend ◽  
Uwe Urmoneit ◽  
Stephan Roth ◽  
Michael Schmidt
Keyword(s):  
Thermal Damage ◽  
Laser Sintering ◽  
Conductive Adhesive ◽  
Flexible Production ◽  
Sintering Process ◽  
Building Process ◽  
In Situ Generation ◽  
Functional Components

Embedding stereolithography (eSLA) is an additive, hybrid process, which provides a flexible production of 3D components and the ability to integrate electrical and optical conductive structures and functional components within parts. However, the embedding of conductive circuits in stereolithography (SLA) parts assumes usage of process technologies, which enables their direct integration of conductive circuits during the layer-wise building process. In this context, a promising method for in-situ generation of conductive circuits is dispensing of conductive adhesive on the current surface of the SLA part and its subsequent sintering. In this paper, the laser sintering (λ = 355 nm) of conductive adhesive mainly consisting of silver nanoparticles is investigated. The work intends to evaluate the curing behavior of the conductive adhesive, the beam-matter-interactions and the thermal damage of the SLA substrate. The investigations revealed a fast and flexible laser sintering process for the generation of conductive circuits with sufficient electrical conductivity and sufficient current capacity load. In this context, a characterization of the conductive structures is done by measuring their electrical resistance and their potential current capacity load.

scholarly journals Shear-Induced and Nanofiber-Nucleated Crystallization of Novel Aliphatic–Aromatic Copolyesters Delineated for In Situ Generation of Biodegradable Nanocomposites

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2315
Author(s):  
Ramin Hosseinnezhad
Keyword(s):  
Shear Rate ◽  
Cooling Rate ◽  
Isothermal Crystallization ◽  
Cellulose Nanofibers ◽  
Crystallization Time ◽  
Nucleation Density ◽  
Shear Rates ◽  
Biodegradable Nanocomposites ◽  
In Situ Generation

The shear-induced and cellulose-nanofiber nucleated crystallization of two novel aliphatic–aromatic copolyesters is outlined due to its significance for the in situ generation of biodegradable nanocomposites, which require the crystallization of nanofibrous sheared inclusions at higher temperatures. The shear-induced non-isothermal crystallization of two copolyesters, namely, poly(butylene adipate-co-succinate-co-glutarate-co-terephthalate) (PBASGT) and poly(butylene adipate-co-terephthalate) (PBAT), was studied following a light depolarization technique. To have a deep insight into the process, the effects of the shear rate, shear time, shearing temperature and cooling rate on the initiation, kinetics, growth and termination of crystals were investigated. Films of 60 μm were subjected to various shear rates (100–800 s−1) for different time intervals during cooling. The effects of the shearing time and increasing the shear rate were found to be an elevated crystallization temperature, increased nucleation density, reduced growth size of lamella stacks and decreased crystallization time. Due to the boosted nucleation sites, the nuclei impinged with each other quickly and growth was hindered. The effect of the cooling rate was more significant at lower shear rates. Shearing the samples at lower temperatures, but still above the nominal melting point, further shifted the non-isothermal crystallization to higher temperatures. As a result of cellulose nanofibers’ presence, the crystallization of PBAT, analyzed by DSC, was shifted to higher temperatures.

In Situ Generation of Amphiphilic Coatings Based on a Self-catalytic Zwitterionic Precursor and Their Antifouling Performance

2021 ◽  
pp. 130115
Author(s):  
Donghui Wang ◽  
Jiakang Xu ◽  
Jinyan Tan ◽  
Jinlong Yang ◽  
Shuxue Zhou
Keyword(s):  
In Situ Generation

P(III)‐Assisted Electrochemical Access to Ureas via in situ Generation of Isocyanates from Hydroxamic Acids

2021 ◽  
Vol 2021 (11) ◽  
pp. 1768-1772
Author(s):  
Haiwen Meng ◽  
Kunhui Sun ◽  
Zhimin Xu ◽  
Lifang Tian ◽  
Yahui Wang
Keyword(s):  
Hydroxamic Acids ◽  
In Situ Generation
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