50 research outputs found
Decarboxylative Suzuki-Miyaura Coupling of (hetero)aromatic carboxylic acids using Iodine as the Terminal Oxidant
No full textA novel methodology for the decarboxylative Suzuki-Miyaura-type coupling has been established. This process uses iodine or a bromine source as both the decarboxylation mediator and the terminal oxidant, thus avoiding the need for stoichiometric amounts of transition metal salts previously required. Our new protocol allows for the construction of valuable biaryl architectures through the coupling of (hetero)aromatic carboxylic acids with arylboronic acids. The scope of this decarboxylative Suzuki reaction has been greatly diversified, allowing for previously inaccessible non-ortho-substituted aromatic acids to undergo this transformation. The procedure also benefits from low catalyst loadings and the absence of stoichiometric transition metal additives
The use of carboxylic acids as traceless directing groups for regioselective C-H bond functionalisation
No full textThe ability to selectively functionalise a specific C-H bond is a long-standing challenge due to the ubiquity of such bonds in organic molecules. One of the most common approaches to overcome this obstacle consists of installing directing groups into substrates to direct the functionalisation towards the desired C-H bond, leaving behind the directing group in the molecule. Alternatively, carboxylic acids have been employed as traceless directing groups that are easily removed after carboxylic acid-directed installation of the desired functionality. This review focuses on the development of this concept and its application to organic synthesis during the last decade.</p
Transition Metal-Free Decarboxylative Iodination:New Routes for Decarboxylative Oxidative Cross-Couplings
No full textConstructing products of high synthetic value from inexpensive and abundant starting materials is of great importance. Aryl iodides are essential building blocks for the synthesis of functional molecules and efficient methods for their synthesis from chemical feedstocks are highly sought after. Here we report a low-cost decarboxylative iodination that occurs simply from readily available benzoic acids and I2. The reaction is scalable and the scope and robustness of the reaction is thoroughly examined. Mechanistic studies suggest that this reaction does not proceed via a radical mechanism, which is in contrast to classical Hunsdiecker-type decarboxylative halogenations. In addition, DFT studies allow comparisons to be made between our procedure and current transition metal-catalyzed decarboxylations. The utility of this procedure is demonstrated in its application to oxidative cross-couplings of aromatics via decarboxylative/C–H or double decarboxylative activations that use I2 as the terminal oxidant. This strategy allows the preparation of biaryls previously inaccessible via decarboxylative methods and holds other advantages over existing decarboxylative oxidative couplings as stoichiometric transition metals are avoided
Transition-Metal-Free Decarboxylative Bromination of Aromatic Carboxylic Acids
No full textMethods for the conversion of aliphatic acids to alkyl halides have progressed significantly over the past century, however, the analogous decarboxylative bromination of aromatic acids has remained a longstanding challenge. The development of efficient methods for the synthesis of aryl bromides is of great importance as they are versatile reagents in synthesis and are present in many functional molecules. Herein we report a transition metal-free decarboxylative bromination of aromatic acids. The reaction is applicable to many electron-rich aromatic and heteroaromatic acids which have previously proved poor substrates for Hunsdiecker-type reactions. In addition, our preliminary mechanistic study suggests that radical intermediates are not involved in this reaction, which is in contrast to classical Hunsdiecker-type reactivity. Overall, the process demonstrates a useful method for producing valuable reagents from inexpensive and abundant starting materials
Allocution de M. Henri Gauthier : décès de James Edward Quibell
No full textGauthier Henri. Allocution de M. Henri Gauthier : décès de James Edward Quibell. In: Bulletin de l'Institut d'Egypte, tome 18, fascicule 2, 1935. p. 252
Transition Metal Free Decarboxylative Halogenation and its Application in Cross-Coupling Chemistry
No full textTowards in-situ Psychological Profiling of Cybercriminals Using Dynamically Generated Deception Environments
No full textCybercrime is estimated to cost the global economy almost \$10 trillion
annually and with businesses and governments reporting an ever-increasing
number of successful cyber-attacks there is a growing demand to rethink the
strategy towards cyber security. The traditional, perimeter security approach
to cyber defence has so far proved inadequate to combat the growing threat of
cybercrime. Cyber deception offers a promising alternative by creating a
dynamic defence environment. Deceptive techniques aim to mislead attackers,
diverting them from critical assets whilst simultaneously gathering cyber
threat intelligence on the threat actor. This article presents a
proof-of-concept (POC) cyber deception system that has been developed to
capture the profile of an attacker in-situ, during a simulated cyber-attack in
real time. By dynamically and autonomously generating deception material based
on the observed attacker behaviour and analysing how the attacker interacts
with the deception material, the system outputs a prediction on the attacker's
motive. The article also explores how this POC can be expanded to infer other
features of the attacker's profile such as psychological characteristics. By
dynamically and autonomously generating deception material based on observed
attacker behaviour and analysing how the attacker interacts with the deception
material, the system outputs a prediciton on the attacker's motive. The article
also explores how this POC can be expanded to infer other features of the
attacker's profile such as psychological characteristics.Comment: 16 pages, 4 figures, 6 table
James E. Quibell's records on Saqqara in the archives of Alexandre Varille
No full textThis paper provides an overview of some archival materials from James E. Quibell archive, which is preserved at the Università degli Studi di Milano (State University of Milan, Italy). This wealth of materials (more than 3500 photographic prints, notebooks, etc.) is the object of an on-going project supported by a grant from The Michela Schiff Giorgini Foundation started in 2014. The paper presents some general considerations that emerged from the analysis of the photographs and illustrates through some different case studies the importance of the discovery of this documentation as well as that of the handwritten one. Besides documenting the major discoveries made by Quibell in Saqqara, the archival materials preserved in Milan is precious not only for the archaeological research stricto sensu, but also for the history of antiquities collecting and provides plenty of information on how could be working in Saqqara at the beginning of the XXth Century
Program development for the BMO UNBC Downtown Business Centre of Excellence
No full textThis paper discusses programming and possible uses for the University of Northern British Columbia's downtown campus. Thirty individuals working throughout the downtown core of Prince George, BC, were interviewed to gather information about the programs that would be of most interest to themselves and their organizations. A literature review showed that the location of a program was important but was secondary to the quality and relevance of the course. The interview results supported the hypothesis people working in the downtown core are most interested in career or work related programming. There was overwhelming support for courses at the downtown campus and participants had strong views on the time of day and week when courses and informational sessions should be held. The interviews further showed that the community was interested in utilizing the location for meetings, events and courses they planned to hold. This paper clarifies the interests of the downtown community in relation to the university's presence in the downtown core.The original print copy of this thesis may be available here: http://wizard.unbc.ca/record=b143507
exserta
No full textCarex exserta Mack.shorthair sedgeN.E. face of 9771 Black Pk., 3/4 m. W-SW of Wes Quall's Stock Camp cabins, S. Fk. Big Crk. above Huntington L. Lodgepole For. (glaciated area) on slopes belowAT FOOT OF LAVA GRAVEL JUST BELOW LAVA BLOCK CAP OF PK. AND AT TOP OF GREAT GRANITE AND LAVA BLOCK TALUS WHICH SLASHES DOWN THRU FOREST BELOW9600'only occas. aboveREPRESENTED HERE BY PINUS MONTICOLA, Talus margined by Lodgepoles-and above by Pinus monti-cola-and carrying scattered Sambucus racemosa, Castanopsis, Eupatorium, Thalictrum, etc. Carex flg. Here in a few rings and terraces, very tough so
