scholarly journals Cyclic(Alkyl)(Amino)Carbene Ligands Enable Cu-Catalyzed Markovnikov Protoboration and Protosilylation of Terminal Alkynes: A Versatile Portal to Functionalized Alkenes

2021 ◽  
Author(s):  
Yang Gao ◽  
Sima Yazdani ◽  
Aaron Kendrick ◽  
Glen Junor ◽  
Douglas Grotjahn ◽  
...  
Keyword(s):  
High Selectivity ◽  
Building Blocks ◽  
Terminal Alkynes ◽  
Carbene Ligands ◽  
Catalytic Systems ◽  
General Solutions ◽  
Shed Light ◽  
Limited Scope

Regioselective hydrofunctionalization of alkynes represents a straightforward route to access alkenyl boronate and silane building blocks. In previously reported catalytic systems, high selectivity is achieved with a limited scope of substrates and/or reagents, with general solutions lacking. Herein, we describe a selective copper-catalyzed Markovnikov hydrofunctionalization of terminal alkynes that is facilitated by strongly donating cyclic (alkyl)(amino)carbene (CAAC) ligands. Using this method, both alkyl- and aryl-substituted alkynes are coupled with a variety of boryl and silyl reagents with high α-selectivity. The reaction is scalable, and the products are versatile intermediates that can participate in various downstream transformations. Preliminary mechanistic experiments shed light on the role of CAAC ligands in this process.

scholarly journals Cyclic(Alkyl)(Amino)Carbene Ligands Enable Cu-Catalyzed Markovnikov Protoboration and Protosilylation of Terminal Alkynes: A Versatile Portal to Functionalized Alkenes

2021 ◽  
Author(s):  
Yang Gao ◽  
Sima Yazdani ◽  
Aaron Kendrick ◽  
Glen Junor ◽  
Douglas Grotjahn ◽  
...  
Keyword(s):  
High Selectivity ◽  
Building Blocks ◽  
Terminal Alkynes ◽  
Carbene Ligands ◽  
Catalytic Systems ◽  
General Solutions ◽  
Shed Light ◽  
Limited Scope

Regioselective hydrofunctionalization of alkynes represents a straightforward route to access alkenyl boronate and silane building blocks. In previously reported catalytic systems, high selectivity is achieved with a limited scope of substrates and/or reagents, with general solutions lacking. Herein, we describe a selective copper-catalyzed Markovnikov hydrofunctionalization of terminal alkynes that is facilitated by strongly donating cyclic (alkyl)(amino)carbene (CAAC) ligands. Using this method, both alkyl- and aryl-substituted alkynes are coupled with a variety of boryl and silyl reagents with high α-selectivity. The reaction is scalable, and the products are versatile intermediates that can participate in various downstream transformations. Preliminary mechanistic experiments shed light on the role of CAAC ligands in this process.

The Role of Time in Theory and Theory Building

2000 ◽  
Vol 26 (4) ◽  
pp. 657-684 ◽  
Author(s):  
Jennifer M. George ◽  
Gareth R. Jones
Keyword(s):  
Subjective Experience ◽  
Building Blocks ◽  
Theory Building ◽  
The Past ◽  
Experience Of Time ◽  
Important Time ◽  
Theoretical Analyses ◽  
Shed Light ◽  
Organizational Literature

Although time has been included in theory and theory building as a boundary condition, this paper argues that time can and should play a more important role because it can change the ontological description and meaning of a theoretical construct and of the relationships between constructs. We suggest that theorists explicitly incorporate multiple aspects of temporality into the “what, how, and why” building blocks of their theories. First, we describe six important time dimensions that we propose are especially relevant to theory building about people, groups, and organizations: the past, future, and present and the subjective experience of time; time aggregations; duration of steady states and rates of change; incremental versus discontinuous change; frequency, rhythms, and cycles; and spirals and intensity. Second, we put forward a series of time-related questions that can serve as a guide or template for improving theory building through the incorporation of temporality into the what, how, and why of theories. Third, we propose how temporality can be incorporated into theorizing, viewed from a process standpoint. Lastly, we demonstrate how the explicit incorporation of time into theoretical analyses may not only lead to better theorizing and theories but also shed light on ongoing debates in the organizational literature.

The Role of Zinc in Thyroid Hormones Metabolism

2019 ◽  
Vol 89 (1-2) ◽  
pp. 80-88 ◽  
Author(s):  
Juliana Soares Severo ◽  
Jennifer Beatriz Silva Morais ◽  
Taynáh Emannuelle Coelho de Freitas ◽  
Ana Letícia Pereira Andrade ◽  
Mayara Monte Feitosa ◽  
...  
Keyword(s):  
Thyroid Hormones ◽  
Scientific Evidence ◽  
Thyroid Stimulating Hormone ◽  
Zinc Transporters ◽  
Serum Concentrations ◽  
Metabolic Adaptations ◽  
Serum T3 ◽  
Regulatory Effects ◽  
Shed Light

Abstract. Thyroid hormones play an important role in body homeostasis by facilitating metabolism of lipids and glucose, regulating metabolic adaptations, responding to changes in energy intake, and controlling thermogenesis. Proper metabolism and action of these hormones requires the participation of various nutrients. Among them is zinc, whose interaction with thyroid hormones is complex. It is known to regulate both the synthesis and mechanism of action of these hormones. In the present review, we aim to shed light on the regulatory effects of zinc on thyroid hormones. Scientific evidence shows that zinc plays a key role in the metabolism of thyroid hormones, specifically by regulating deiodinases enzymes activity, thyrotropin releasing hormone (TRH) and thyroid stimulating hormone (TSH) synthesis, as well as by modulating the structures of essential transcription factors involved in the synthesis of thyroid hormones. Serum concentrations of zinc also appear to influence the levels of serum T3, T4 and TSH. In addition, studies have shown that Zinc transporters (ZnTs) are present in the hypothalamus, pituitary and thyroid, but their functions remain unknown. Therefore, it is important to further investigate the roles of zinc in regulation of thyroid hormones metabolism, and their importance in the treatment of several diseases associated with thyroid gland dysfunction.

The Adult as Foe or Friend?: Childism in Guus Kuijer's Criticism and Fiction

2013 ◽  
Vol 6 (2) ◽  
pp. 205-217 ◽  
Author(s):  
Vanessa Joosen
Keyword(s):  
Children's Literature ◽  
Children’S Literature ◽  
Age Groups ◽  
Children's Books ◽  
Children’S Books ◽  
Memorial Award ◽  
Adult Reader ◽  
Shed Light ◽  
Selection Of

Compared to the attention that children's literature scholars have paid to the construction of childhood in children's literature and the role of adults as authors, mediators and readers of children's books, few researchers have made a systematic study of adults as characters in children's books. This article analyses the construction of adulthood in a selection of texts by the Dutch author and Astrid Lindgren Memorial Award winner Guus Kuijer and connects them with Elisabeth Young-Bruehl's recent concept of ‘childism’ – a form of prejudice targeted against children. Whereas Kuijer published a severe critique of adulthood in Het geminachte kind [The despised child] (1980), in his literary works he explores a variety of positions that adults can take towards children, with varying degrees of childist features. Such a systematic and comparative analysis of the way grown-ups are characterised in children's texts helps to shed light on a didactic potential that materialises in different adult subject positions. After all, not only literary and artistic aspects of children's literature may be aimed at the adult reader (as well as the child), but also the didactic aspect of children's books can cross over between different age groups.

Catalytic Activity of Binary and Triple Systems Based on Redox Inactive Metal Compound, LiSt and Additives of Monodentate Ligands-Modifiers: DMF, HMPA and PhOH, in Selective Ethylbenzene Oxidation with Dioxygen

2016 ◽  
Vol 10 (3) ◽  
pp. 259-270
Author(s):  
Ludmila Matienko ◽  
◽  
Larisa Mosolova ◽  
Vladimir Binyukov ◽  
Gennady Zaikov ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Triple System ◽  
Metal Compound ◽  
Ethylbenzene Oxidation ◽  
Catalytic Systems ◽  
Triple Systems ◽  
Lithium Compound ◽  
Mechanism Of Catalysis ◽  
Monodentate Ligands

Mechanism of catalysis with binary and triple catalytic systems based on redox inactive metal (lithium) compound {LiSt+L2} and {LiSt+L2+PhOH} (L2=DMF or HMPA), in the selective ethylbenzene oxidation by dioxygen into -phenylethyl hydroperoxide is researched. The results are compared with catalysis by nickel-lithium triple system {NiII(acac)2+LiSt+PhOH} in selective ethylbenzene oxidation to PEH. The role of H-bonding in mechanism of catalysis is discussed. The possibility of the stable supramolecular nanostructures formation on the basis of triple systems, {LiSt+L2+PhOH}, due to intermolecular H-bonds, is researched with the AFM method.

Tax evasion in the medical profession An Empirical Study in the General Tax Authority in Iraq

2019 ◽  
Vol 118 (11) ◽  
pp. 80-88
Author(s):  
Ramyar Rzgar Ahmed ◽  
Hawkar Qasim Birdawod ◽  
S. Rabiyathul Basariya
Keyword(s):  
Tax Evasion ◽  
Income Tax ◽  
Medical Profession ◽  
Great Influence ◽  
Tax Law ◽  
Degree Of Confidence ◽  
Medical Professions ◽  
Shed Light

The study dealt with tax evasion in the medical profession, where the problem was the existence of many cases of tax evasion, especially tax evasion in the income tax of medical professions. The aim of the study is to try to shed light on the phenomenon of tax evasion and the role of the tax authority in the development of controls and means that reduce the phenomenon of tax evasion. The most important results of the low level of tax awareness and lack of knowledge of the tax law and the unwillingness to read it and the sense of taxpayers unfairness of the tax all lead to an increase in cases of tax evasion and in suggested tightening control and follow-up on the offices of auditors, through the investigation and auditing The reports of certified accountants and the use of computers for this purpose in order to raise the degree of confidence in these reports and bring them closer to the required truth and coordination and cooperation with the Union of Accountants and Auditors and inform them about each case of violations of the auditors and accountants N because of its great influence in the rejection of the organization of the accounts and not to ratify fake accounts lead to show taxpayers accounts on a non-truth in order to tax evasion.

The Baluch, Sunnism and the State in Iran

2017 ◽  
Author(s):  
Stéphane A. Dudoignon
Keyword(s):  
South Asia ◽  
South Asian ◽  
Social Life ◽  
The State ◽  
First Century ◽  
Local Democracy ◽  
Oasis Area ◽  
Shed Light

Since 2002, Sunni jihadi groups have been active in Iranian Baluchistan without managing to plunge the region into chaos. This book suggests that a reason for this, besides Tehran’s military responses, has been the quality of Khomeini and Khamenei’s relationship with a network of South-Asia-educated Sunni ulama (mawlawis) originating from the Sarbaz oasis area, in the south of Baluchistan. Educated in the religiously reformist, socially conservative South Asian Deoband School, which puts the madrasa at the centre of social life, the Sarbazi ulama had taken advantage, in Iranian territory, of the eclipse of Baluch tribal might under the Pahlavi monarchy (1925-79). They emerged then as a bulwark against Soviet influence and progressive ideologies, before rallying to Khomeini in 1979. Since the turn of the twenty-first century, they have been playing the role of a rampart against Salafi propaganda and Saudi intrigues. The book shows that, through their alliance with an Iranian Kurdish-born Muslim-Brother movement and through the promotion of a distinct ‘Sunni vote’, they have since the early 2000s contributed towards – and benefitted from – the defence by the Reformist presidents Khatami (1997-2005) and Ruhani (since 2013) of local democracy and of the minorities’ rights. They endeavoured to help, at the same time, preventing the propagation of jihadism and Sunni radicalisation to Iran – at least until the ISIS/Daesh-claimed attacks of June 2017, in Tehran, shed light on the limits of the Islamic Republic’s strategy of reliance on Deobandi ulama and Muslim-Brother preachers in the country’s Sunni-peopled peripheries.

Wetlands Explained

2001 ◽  
Author(s):  
William M. Lewis
Keyword(s):  
Public Attitudes ◽  
Conservation Policy ◽  
Compact Form ◽  
The Political ◽  
Social Conflicts ◽  
Science And Policy ◽  
Ecosystem Science ◽  
Wetland Regulation ◽  
Shed Light

This book brings together in compact form a broad scientific and sociopolitical view of US wetlands. This primer lays out the science and policy considerations to help in navigating this branch of science that is so central to conservation policy, ecosystem science and wetland regulation. It gives explanations of the attributes, functions and values of our wetlands and shows how and why public attitudes toward wetlands have changed, and the political, legal, and social conflicts that have developed from legislation intended to stem the rapid losses of wetlands. The book describes the role of wetland science in facilitating the evolution of a rational and defensible system for regulating wetlands and will shed light on many of the problems and possibilities facing those who quest to protect and conserve our wetlands.

Islam, Gender, and Democracy in Comparative Perspective

2017 ◽  
Keyword(s):  
Human Rights ◽  
Comparative Literature ◽  
Gender Equality ◽  
Gender Inequality ◽  
Women's Rights ◽  
Women’S Rights ◽  
Muslim Countries ◽  
And Gender ◽  
Shed Light

This volume reframes the debate around Islam and women’s rights within a broader comparative literature. It examines the complex and contingent historical relationships between religion, secularism, democracy, law, and gender equality. Part I addresses the nexus of religion, law, gender, and democracy through different disciplinary perspectives (sociology, anthropology, political science, law). Part II localizes the implementation of this nexus between law, gender, and democracy, and provides contextualized responses to questions raised in Part I. The contributors explore the situation of Muslim women’s rights vis-à-vis human rights to shed light on gender politics in the modernization of the nation and to ponder over the role of Islam in gender inequality across different Muslim countries.

The Role of the City in Merovingian Francia

2020 ◽  
pp. 581-610
Author(s):  
S. T. Loseby
Keyword(s):  
Roman Empire ◽  
Urban Communities ◽  
Late Antiquity ◽  
Building Blocks ◽  
Urban Network ◽  
City Councils ◽  
Royal Courts ◽  
Range Of Functions ◽  
Fierce Competition

The Merovingians inherited an urban network from the Roman Empire that remained substantially intact. Although Gallic cities had long been declining in extent and sophistication, during late antiquity their landscapes were adapted to contemporary priorities through the provision of walls and churches, and their politics was transformed by the emergence of bishops as leaders of urban communities. When the upper tiers of imperial administration disappeared, this equipped the vast majority of cities to survive as the basic building blocks of Merovingian kingdoms that were initially conceived as aggregations of city–territories. In ruling through their cities, the Merovingians expanded upon existing mechanisms for the extraction of taxes and services, while relying on centrally appointed bishops and counts rather than city councils for the projection of their authority. This generated fierce competition between kings for control of cities and among local elites for positions of power within them. In the later Merovingian period, however, the significance of cities diminished as stable territorial kingdoms emerged, political practice was centralized around the royal courts, and the Roman administrative legacy finally disintegrated. But the cities remained preeminent religious centers, and, with the beginnings of economic revival, continued to perform a range of functions unmatched by other categories of settlement.

Sign in / Sign up

Export Citation Format

Share Document