Interrogating the Crucial Interactions at Play in the Chiral Cation-Directed Enantioselective Borylation of Arenes.

Rendering a common ligand scaffold anionic and then pairing it with a chiral cation represents an alternative strategy for developing enantioselective versions of challenging transformations, as has been recently demonstrated in the enantioselective borylation of arenes using a quinine-derived chiral cation. A significant barrier to the further generalization of this approach is the lack of understanding of the specific interactions involved between the cation, ligand, and substrate, given the complexity of the system. We have embarked on a detailed computational study probing the mechanism, the key noncovalent interactions involved, and potential origin of selectivity for the desymmetrizing borylation of two distinct classes of substrate. We describe a deconstructive, stepwise approach to tackling this complex challenge, which involves building up a detailed understanding of the pairwise components of the nominally three component system before combining together into the full 263-atom reactive complex. This approach has revealed substantial differences in the noncovalent interactions occurring at the stereodetermining transition state for C-H oxidative addition to iridium for the two substrate classes. Each substrate engages in a unique mixture of diverse interactions, a testament to the rich and privileged structure of the cinchona alkaloid-derived chiral cations. Throughout the study, experimental support is provided, and this culminates in the discovery that prochiral phosphine oxide substrates, lacking hydrogen bond donor functionality, can also give very encouraging levels of enantioselectivity, potentially through direct interactions with the chiral cation. We envisage that the findings in this study will spur further developments in using chiral cations as controllers in asymmetric transition-metal catalysis.

Hydrogen Atom Transfer Driven Enantioselective Minisci Reaction of Alcohols.

Catalytic enantioselective Minisci reactions have recently been developed but all instances so far utilize α-amino radical coupling partners. We report a substantial evolution of the enantioselective Minisci reaction that enables α-hydroxy radicals to be used, providing valuable enantioenriched secondary alcohol products. This is achieved through the direct oxidative coupling of two C-H bonds on simple alcohol and pyridine partners through a hydrogen atom transfer (HAT)-driven approach: a challenging process to achieve due to the numerous side reactions that can occur. Our approach is highly regioselective as well as highly enantioselective. Dicumyl peroxide, upon irradiation with 390 nm light, serves as both HAT reagent and oxidant whilst selectivity is controlled by use of a chiral phosphoric acid catalyst. Computational and experimental evidence provide mechanistic insight as to the origin of selectivity, revealing a stereodetermining deprotonation step distinct from the analogous reaction of amide-containing substrates.

3D engineering for optic neuropathy treatment.

Ocular disorders, such as age-related macular degeneration (AMD), diabetic retinopathy (DR), retinitis pigmentosa (RP), and glaucoma, can cause irreversible visual loss, and affect the quality of life of millions of patients. However, only very few 3D systems can mimic human ocular pathophysiology, especially the retinal degenerative diseases, which involve the loss of retinal ganglion cells (RGCs), photoreceptors, or retinal pigment epithelial cells (RPEs). In this review, we discuss current progress in the 3D modeling of ocular tissues, and review the use of the aforementioned technologies for optic neuropathy treatment according to the categories of associated disease models and their applications in drug screening, mechanism studies, and cell and gene therapies.

Enantioselective remote C-H activation directed by a chiral cation.

Chiral cations have been used extensively as organocatalysts, but their application to rendering transition metal-catalyzed processes enantioselective remains rare. This is despite the success of the analogous charge-inverted strategy in which cationic metal complexes are paired with chiral anions. We report here a strategy to render a common bipyridine ligand anionic and pair its iridium complexes with a chiral cation derived from quinine. We have applied these ion-paired complexes to long-range asymmetric induction in the desymmetrization of the geminal diaryl motif, located on a carbon or phosphorus center, by enantioselective C-H borylation. In principle, numerous common classes of ligand could likewise be amenable to this approach.

Unobtrusive Observation of Team Learning Attributes in Digital Learning.

This article presents a new framework for unobtrusive observation analytics of knowledge and skills-in-action through continuous collection of data from individuals while they interact with digital assets either as individuals or on problem-solving teams. The framework includes measures of the skill and knowledge areas of collaboration, creativity, personal learning, problem solving, and global sustainability, which are observed during natural production and use of communications, intentional artifacts, and resources in a digital learning space designed for self-directed and team-based learning challenges. The article describes the digital context for data collection and shows some example data and analyses.

Student Attitudes toward Learning Analytics in Higher Education: "The Fitbit Version of the Learning World".

Increasingly, higher education institutions are exploring the potential of learning analytics to predict student retention, understand learning behaviors, and improve student learning through providing personalized feedback and support. The technical development of learning analytics has outpaced consideration of ethical issues surrounding their use. Of particular concern is the absence of the student voice in decision-making about learning analytics. We explored higher education students' knowledge, attitudes, and concerns about big data and learning analytics through four focus groups (N = 41). Thematic analysis of the focus group transcripts identified six key themes. The first theme, "Uninformed and Uncertain," represents students' lack of knowledge about learning analytics prior to the focus groups. Following the provision of information, viewing of videos and discussion of learning analytics scenarios three further themes; "Help or Hindrance to Learning," "More than a Number," and "Impeding Independence"; represented students' perceptions of the likely impact of learning analytics on their learning. "Driving Inequality" and "Where Will it Stop?" represent ethical concerns raised by the students about the potential for inequity, bias and invasion of privacy and the need for informed consent. A key tension to emerge was how "personal" vs. "collective" purposes or principles can intersect with "uniform" vs. "autonomous" activity. The findings highlight the need the need to engage students in the decision making process about learning analytics.