Acid-Catalyzed In Situ Generation of Less Accessible or UnprecedentedN-Boc Imines fromN-Boc Aminals

2013 ◽  
Vol 125 (21) ◽  
pp. 5642-5644 ◽  
Author(s):  
Taichi Kano ◽  
Taiga Yurino ◽  
Daisuke Asakawa ◽  
Keiji Maruoka
2019 ◽  
Vol 15 ◽  
pp. 1061-1064 ◽  
Author(s):  
Alexei Lukin ◽  
Anna Bakholdina ◽  
Anna Kryukova ◽  
Alexander Sapegin ◽  
Mikhail Krasavin

A three-component reaction involving in situ generation of propargylureas and subsequent Zn(OTf)2-mediated cyclocondensation with a primary amine yielded trisubstituted 2-aminoimidazoles. These findings are in contrast to the previously reported base-promoted unimolecular cyclization of propargylureas (leading to 2-imidazolones) and extend the range of Lewis acid-catalyzed azole syntheses based on N-carbonyl propargylamines.


ChemInform ◽  
2013 ◽  
Vol 44 (40) ◽  
pp. no-no
Author(s):  
Taichi Kano ◽  
Taiga Yurino ◽  
Daisuke Asakawa ◽  
Keiji Maruoka

2013 ◽  
Vol 52 (21) ◽  
pp. 5532-5534 ◽  
Author(s):  
Taichi Kano ◽  
Taiga Yurino ◽  
Daisuke Asakawa ◽  
Keiji Maruoka

Author(s):  
Kazumasa Funabiki ◽  
Toshiya Gotoh ◽  
Ryunosuke Kani ◽  
Toshiyasu Inuzuka ◽  
Yasuhiro Kubota

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


2018 ◽  
Author(s):  
Haley Albright ◽  
Paul S. Riehl ◽  
Christopher C. McAtee ◽  
Jolene P. Reid ◽  
Jacob R. Ludwig ◽  
...  

<div>Catalytic carbonyl-olefin metathesis reactions have recently been developed as a powerful tool for carbon-carbon bond</div><div>formation. However, currently available synthetic protocols rely exclusively on aryl ketone substrates while the corresponding aliphatic analogs remain elusive. We herein report the development of Lewis acid-catalyzed carbonyl-olefin ring-closing metathesis reactions for aliphatic ketones. Mechanistic investigations are consistent with a distinct mode of activation relying on the in situ formation of a homobimetallic singly-bridged iron(III)-dimer as the active catalytic species. These “superelectrophiles” function as more powerful Lewis acid catalysts that form upon association of individual iron(III)-monomers. While this mode of Lewis acid activation has previously been postulated to exist, it has not yet been applied in a catalytic setting. The insights presented are expected to enable further advancement in Lewis acid catalysis by building upon the activation principle of “superelectrophiles” and broaden the current scope of catalytic carbonyl-olefin metathesis reactions.</div>


2020 ◽  
Vol 24 ◽  
Author(s):  
Wengui Wang ◽  
Shoufeng Wang

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.


2021 ◽  
Author(s):  
Thomas Richards ◽  
Jonathan H. Harrhy ◽  
Richard J. Lewis ◽  
Alexander G. R. Howe ◽  
Grzegorz M. Suldecki ◽  
...  

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

2014 ◽  
Vol 1038 ◽  
pp. 75-81
Author(s):  
Bernd Niese ◽  
Philipp Amend ◽  
Uwe Urmoneit ◽  
Stephan Roth ◽  
Michael Schmidt

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.


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