124,959 research outputs found
Chiral Phosphoric Acid Catalysis: The Terada Model Revisited
No full textSince Akiyama and Terada independently
reported the introduction
of chiral phosphoric acids (CPAs) as effective catalysts for Mannich-type
reactions in 2004, the field of CPA catalysis has grown immensely.
Terada reported in 2008 the first example of the activation of aldehydes
by a CPA. Based on density functional theory (DFT) calculations, Terada
proposed a dual activation mode for this enantioselective aza–ene-type
reaction between an aldehyde and an enecarbamate. In this model, hydrogen
bonds between the catalyst’s hydroxyl group and the carbonyl
oxygen and the catalyst’s PO and the formyl proton
were observed; the nucleophile then attacks without coordination to
the catalyst. This reaction model provided the mechanistic basis for
understanding Terada’s reaction and many other asymmetric transformations.
In the present study, DFT calculations are reported that identify
a lower-energy mechanism for this landmark reaction. In this new model,
hydrogen bonds between the catalyst’s hydroxyl group and the
aldehyde oxygen and the catalyst’s PO and the NH group
of the enecarbamate are seen. The new model rationalizes the stereoselective
outcome of Terada’s reaction and offers insight into why a
more sterically demanding catalyst gives lower levels of enantioselectivity
Chiral Phosphoric Acid Catalysis: The Terada Model Revisited
No full textSince Akiyama and Terada independently reported the introduction of chiral phosphoric acids (CPAs) as effective catalysts for Mannich-type reactions in 2004, the field of CPA catalysis has grown immensely. Terada reported in 2008 the first example of the activation of aldehydes by a CPA. Based on density functional theory (DFT) calculations, Terada proposed a dual activation mode for this enantioselective aza–ene-type reaction between an aldehyde and an enecarbamate. In this model, hydrogen bonds between the catalyst’s hydroxyl group and the carbonyl oxygen and the catalyst’s P═O and the formyl proton were observed; the nucleophile then attacks without coordination to the catalyst. This reaction model provided the mechanistic basis for understanding Terada’s reaction and many other asymmetric transformations. In the present study, DFT calculations are reported that identify a lower-energy mechanism for this landmark reaction. In this new model, hydrogen bonds between the catalyst’s hydroxyl group and the aldehyde oxygen and the catalyst’s P═O and the NH group of the enecarbamate are seen. The new model rationalizes the stereoselective outcome of Terada’s reaction and offers insight into why a more sterically demanding catalyst gives lower levels of enantioselectivity
Exclamation en japonais
No full textTerada Akira. Exclamation en japonais. In: Faits de langues, n°6, Septembre 1995. L'exclamation. pp. 211-216
Naoki Inagaki, La littérature française et les Japonais
No full textTerada Mitsunori. Naoki Inagaki, La littérature française et les Japonais. In: Romantisme, 1995, n°87. Fins de siècle. pp. 125-126
Naoki Inagaki, La littérature française et les Japonais
No full textTerada Mitsunori. Naoki Inagaki, La littérature française et les Japonais. In: Romantisme, 1995, n°87. Fins de siècle. pp. 125-126
No, de et node ou la (re)construction de la suite (chrono)logique
No full textTerada Akira. No, de et node ou la (re)construction de la suite (chrono)logique. In: Faits de langues, n°1, Mars 1993. Motivation et iconicité. pp. 137-140
La phrase japonaise et son double dispositif d'intégration des noms : les particules dites relationnelles et casuelles
No full textTamba Irène, Terada Akira. La phrase japonaise et son double dispositif d'intégration des noms : les particules dites relationnelles et casuelles. In: Langages, 25ᵉ année, n°104, 1991. Intégration syntaxique et cohérence discursive. pp. 33-45
A Multi-Language Comparison of Influences on Author Verification using Character N-Grams
No full textWe create a new multi-language corpus for author verification based on Wikipedia talkpages, and evaluate the influence that differences in topic and time have on character n-gram author profiles. Topic alignment between two texts is found to increase author verification precision, and an authors writing style is found to change over time, but not more significantly after 3 years than after 1 year.Information ArchitectureWISElectrical Engineering, Mathematics and Computer Scienc
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
The vanishing author in computer-generated works: a critical analysis of recent Australian case law
No full textAbstract
The use of software is ubiquitous in the creation of many copyright works, yet the requirement in copyright law that every work have a human author who engages in independent intellectual effort means that its use may prevent copyright subsistence. Several recent Australian cases have refocused attention on authorship as an essential criterion of copyright subsistence, and these cases suggest that much computer-produced output may be authorless and thus lack copyright protection. This article, the first in a two-part series, analyses how each case deals with the question of authorship of computer-produced works and why the use of software diminishes copyright protection for a significant number of computer-generated works. The article critiques the application of conventional notions of human authorship developed in the pre-computer age to modern productions and suggests alternative approaches to authorship that satisfy both the major objectives of copyright policy and the need to adapt to the computer age. The article argues that, without a broader judicial approach to authorship of computer-generated works, Parliament must remedy the lacuna in protection for these ‘authorless’ works. Possible solutions for reform are suggested. In a forthcoming article, the author comprehensively examines those reform proposals
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