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Tetraarylmethanes (TAMs) contain a carbon atom bound to four aryl groups. They have found diverse applications in chemistry, materials science, chemical biology and medicinal chemistry because of their unique 3-dimensional structures. As a reflection of the high demand for TAMs, over 32,000 unique TAMs have been prepared. The distinct structures of TAMs and the crowded nature of the central carbon atom require different strategies for their syntheses. Herein we present the first review on the synthesis of TAMs, from classical approaches to modern methods, including enantioselective syntheses of TAMs. We provide a critical evaluation of methods and highlight important directions for future research into the synthesis of this aesthetically pleasing and very useful class of spherical structures.

With its varied landscape of hills and mountains, New Zealand has an abundance of marginal land on its slopes. This land is currently used in a variety of enterprises, such as pasture and farmland. However, marginal land is typically associated with higher rates of erosion, shallow topsoil, expensive fencing, and other issues like livestock deaths from falls. There is currently interest in deploying these marginal lands to different uses to align with several environmental and production-related goals. This paper contributes to the discussion on marginal land by exploring three different scenarios related to afforestation in the Manawatu catchment area. To analyze these scenarios, we bring together several complex and spatially explicit data sets which are linked using economic modeling tools and benefits transfer methods. The combination of these tools and data sets allows us to produce several important quantitative and qualitative outputs. Where possible, quantitative predictions are monetized, allowing a benefit-cost analysis of the proposed scenarios.

Governments need tools to analyze trade-offs for freshwater policy, yet valuation estimates from the literature can be difficult to deploy in a policy setting. Obstacles to benefit transfer include (i) difficulties in scaling up local estimates, (ii) water quality attributes that cannot be linked to policy, and (iii) surveys positing large, unrealistic water quality changes. Focusing on freshwater rivers and streams in New Zealand, we develop and implement a nationwide discrete choice stated preference study aimed at future benefit transfer. The stated provision mechanism and environmental commodity being valued are specified at the regional council level, which is the administrative unit for policy implementation. The survey is administered on a national scale with three attributes – nutrients, water clarity, and E. coli levels – which were chosen to align with government policy levers and salience to the public. Estimation results demonstrate positive and significant willingness to pay values for improvements in each attribute, with magnitudes that are comparable to a recent referendum vote on a water quality tax. To illustrate the utility of our study, we apply the results to a recent policy analyzed by New Zealand’s Ministry for the Environment and estimate nationwide annual benefits of NZ $115 million ($77 million USD).

The profens belong to a class of nonsteroidal anti-inflammatory drugs (NSAIDs), which exert significant anti-inflammatory, analgesic, antipyretic and other pharmacological effects. A considerable number of catalytic asymmetric strategies for the synthesis of enantioenriched profens have been introduced. Herein are outlined recent trends and developments of promising catalytic enantioselective systems for the generation of profens and their derivatives. According to the reaction type, we divided these transformations into three categories: Transition metal-catalyzed asymmetric hydrogenations, transition metal-catalyzed asymmetric cross-couplings and organocatalytic asymmetric transformations. Overviews of generic reaction mechanisms are presented. Ideally, this tutorial review will motivate further interest in the catalytic asymmetric synthesis of highly enantioenriched profens.

Abstract Background Association of chromatin with lamin proteins at the nuclear periphery has emerged as a potential mechanism to coordinate cell type-specific gene expression and maintain cellular identity via gene silencing. Unlike many histone modifications and chromatin-associated proteins, lamina-associated domains (LADs) are mapped genome-wide in relatively few genetically normal human cell types, which limits our understanding of the role peripheral chromatin plays in development and disease. Results To address this gap, we map LAMIN B1 occupancy across twelve human cell types encompassing pluripotent stem cells, intermediate progenitors, and differentiated cells from all three germ layers. Integrative analyses of this atlas with gene expression and repressive histone modification maps reveal that lamina-associated chromatin in all twelve cell types is organized into at least two subtypes defined by differences in LAMIN B1 occupancy, gene expression, chromatin accessibility, transposable elements, replication timing, and radial positioning. Imaging of fluorescently labeled DNA in single cells validates these subtypes and shows radial positioning of LADs with higher LAMIN B1 occupancy and heterochromatic histone modifications primarily embedded within the lamina. In contrast, the second subtype of lamina-associated chromatin is relatively gene dense, accessible, dynamic across development, and positioned adjacent to the lamina. Most genes gain or lose LAMIN B1 occupancy consistent with cell types along developmental trajectories; however, we also identify examples where the enhancer, but not the gene body and promoter, changes LAD state. Conclusions Altogether, this atlas represents the largest resource to date for peripheral chromatin organization studies and reveals an intermediate chromatin subtype.

Oxadiazoles are five-membered ring heterocycles comprising an oxygen and two nitrogens, and those with the 1,2,4-oxadiazole skeleton are of interest due to their prevalence in biologically active compounds. Here, the authors report a transition metal-free [3+2]-cycloaddition of nitroarenes with 2-azaallyl anions under basic conditions to access 2,5-dihydro-1,2,4-oxadiazoles.

Enantioenriched α-aryl propionic acids are an important class of nonsteroidal anti-inflammatory medications. Here the authors use a visible-light-promoted photoredox/nickel catalyzed method to form such compunds via a three-component alkyl arylation of acrylates.

Allylation of nucleophiles with less reactive electrophiles, such as carbonates, usually requires a transition-metal catalyst. Here, the authors show a transition-metal-free allylation strategy with allyl ether electrophiles to form homoallylic amine derivatives in up to 92% yield.

Ce(IV) organometallic compounds are rare due to Ce(IV) being a powerful oxidant. Herein, the authors explore the covalency of a pair of organocerium complexes bearing a Ce(IV)-C(aryl) bond and examine their structure by NMR spectroscopy, X-ray diffraction analysis, and computational calculations.

N-Arylation of NH-diaryl sulfoximines faces synthetic challenges among reported methods. Here, the authors present a mild copper-catalyzed photoredox dehydrogenative Chan-Lam coupling of free diaryl sulfoximines and arylboronic acids via an auto-catalytic process.

Homoenolates and their higher homologs have much potential, albeit largely unrealized, in transition metal catalysis. Here, the authors report the nickel-catalyzed generation of homoenolates, and their higher homologs, via decarbonylation of cyclic anhydrides, which then undergo cross-coupling with alkyl bromides.

Formation of tertiary C(sp3)-C bonds is a formidable challenge due to steric interactions and low barriers for isomerization of intermediates. Here, the authors show a Ni-catalyzed migratory 3,3-difluoroallylation of unactivated alkyl bromides at remote tertiary carbon centers.

New Zealand’s iconic bird species, the kiwi, is facing significant threats from dogs. Dogs walked off leash or left outside frequently kill fragile kiwi, posing a major social issue. Local governments have spread awareness through billboards, pamphlets, and other media, but there are no empirical analyses of message effectiveness or targeting. There is a dearth of research on behavioural interventions in conservation, where pro-environmental behaviour is typically costly to individuals. This study uses a randomised control trial (RCT) to test the effectiveness of four different messages on a local policy for dog registration, using thousands of households. The RCT aims to increase dog registration fees, which, although compulsory, have low compliance in some areas. Results suggest considerable heterogeneity in response across messages, with only messages focussed on kiwi conservation and dog attacks having an impact on registration, and only in some groups. A social norm /”nudge”-based message had no effect. Results should help design future messaging programs, as well as raise funds for conservation through additional registration fees. This study is one of the first to use an evidence-based approach for conservation messages in a critical area and provides several implications for future policy and engagement campaigns.

The ring-opening and functionalization of electronically unbiased cyclopropanes is highly challenging to achieve in a regioselective fashion. Here, the authors report a mild photoredox-coupled oxoamination of electronically unactivated aryl cyclopropanes with simple azaarenes and molecular oxygen.

Despite concerted efforts to identify CNS regeneration strategies, an incomplete understanding of how the needed molecular machinery is regulated limits progress. Here we use models of lateral compression and FEJOTA clip contusion-compression spinal cord injury (SCI) to identify the thrombin receptor (Protease Activated Receptor 1 (PAR1)) as an integral facet of this machine with roles in regulating neurite growth through a growth factor- and cholesterol-dependent mechanism. Functional recovery and signs of neural repair, including expression of cholesterol biosynthesis machinery and markers of axonal and synaptic integrity, were all increased after SCI in PAR1 knockout female mice, while PTEN was decreased. Notably, PAR1 differentially regulated HMGCS1, a gene encoding a rate-limiting enzyme in cholesterol production, across the neuronal and astroglial compartments of the intact versus injured spinal cord. Pharmacologic inhibition of cortical neuron PAR1 using vorapaxar in vitro also decreased PTEN and promoted neurite outgrowth in a cholesterol dependent manner, including that driven by suboptimal brain derived neurotrophic factor (BDNF). Pharmacologic inhibition of PAR1 also augmented BDNF-driven HMGCS1 and cholesterol production by murine cortical neurons and by human SH-SY5Y and iPSC-derived neurons. The link between PAR1, cholesterol and BDNF was further highlighted by demonstrating that the deleterious effects of PAR1 over-activation are overcome by supplementing cultures with BDNF, cholesterol or by blocking an inhibitor of adenylate cyclase, Gαi. These findings document PAR1-linked neurotrophic coupling mechanisms that regulate neuronal cholesterol metabolism as an important component of the machinery regulating CNS repair and point to new strategies to enhance neural resiliency after injury.

Fixation of CO2 in organic molecules is an area of great interest due to the implications in sustainable chemistry. Here, the authors show a visible light-mediated hydrocarboxylation of ketimines with atmospheric CO2 to afford a number of α,α–diaryl α-amino acid derivatives.

Amines are common targets in synthetic chemistry as they often display biological activity. Here, the authors report a one-pot aminobenzylation of aldehydes with readily available toluenes in presence of a sodium amide derivative and a cesium salt additive generating an array of valuable 1,2-diarylethylamine compounds.

Polymerization reactions are often catalysed by metal compounds and hence there are concerns surrounding toxicity, cost and environmental friendliness. Here the authors show sulfenate anions as organocatalysts for benzylic chloromethyl-coupling polymerization reactions to form poly(stilbene)s.

Molecules with 4 aryl groups attached to a central carbon atom have proven challenging to synthesize despite their attractiveness for a variety of applications. Here the authors report a Pd-catalysed arylation of di- and triarylmethanes, giving a high-yielding route to an array of tetraarylmethanes.

Methacrolein oxide (MACR-oxide) is a four-carbon, resonance-stabilized Criegee intermediate produced from isoprene ozonolysis, yet its reactivity is not well understood. This study identifies the functionalized hydroperoxide species, 1-hydroperoxy-2-methylallyl formate (HPMAF), generated from the reaction of MACR-oxide with formic acid using multiplexed photoionization mass spectrometry (MPIMS, 298 K = 25 °C, 10 torr = 13.3 hPa). Electronic structure calculations indicate the reaction proceeds via an energetically favorable 1,4-addition mechanism. The formation of HPMAF is observed by the rapid appearance of a fragment ion at m/z 99, consistent with the proposed mechanism and characteristic loss of HO2 upon photoionization of functional hydroperoxides. The identification of HPMAF is confirmed by comparison of the appearance energy of the fragment ion with theoretical predictions of its photoionization threshold. The results are compared to analogous studies on the reaction of formic acid with methyl vinyl ketone oxide (MVK-oxide), the other four-carbon Criegee intermediate in isoprene ozonolysis.

Invasive mammals are a primary threat to New Zealand's endemic species. In remote areas, aerial delivery of poison is the preferred method of pest management, although it faces some public backlash. Novel pest control technologies are currently being investigated as alternatives but may face similar concerns. To investigate potential social and demographic determinants of public perceptions of new methods for pest control, we conducted a national choice experiment, focused on several novel technologies: gene drives, Trojan females, and species-specific poisons. We found that preferences strongly depend on the type of technology, with Trojan female technology strictly preferred to the other two. Although several characteristics affected preferences in predictable ways - education, trust in science, and liberal political leaning increased acceptance - the same did not hold with preferences for aerial delivery. Our results are useful for targeting future engagement campaigns and leveraging existing efforts.

Elasmobranch diets consist of high quantities of protein and lipids, but very low levels of carbohydrates including glucose. Reflecting this diet, most tissues use lipids and ketone bodies as their main metabolic fuel. However, the rectal gland has been shown to be dependent on glucose as a fuel, so we hypothesized that glucose transporters (GLUTs) would be present and upregulated in the gland during times of activation (e.g. following a meal). In this study, we searched for and identified putative class I GLUTs in three elasmobranchs and a holocephalan using transcriptomes, and used these to reconstruct a Bayesian phylogeny. We determined that each of the four species possessed three of the four class I GLUT sequences, but the identities of the isoforms present in each species differed between the elasmobranchs (GLUT1, 3 and 4) and the holocephalan (GLUT1, 2 and 3). We then used qPCR to measure mRNA levels of these GLUTs in the rectal gland, liver, intestine, and muscle of fed and starved spiny dogfish (Squalus suckleyi). The rectal gland data showed higher mRNA levels of GLUT4 in the starved relative to the fed fish. In the muscle, both GLUT1 and 4 were significantly elevated at 24 h post-feeding, as was the case for GLUT4 in the liver. In the intestine on the other hand, GLUT4 was significantly elevated by 6 h post-feeding, remaining elevated through 48 h. We suggest that GLUT4 has taken on the role of GLUT2 in elasmobranchs as the expression patterns observed in the liver and intestine are representative of GLUT2 in other vertebrates.

The branchial mechanism of urea retention in elasmobranchs was investigated using an in vitro isolated-perfused head preparation, as well as in vivo samples, in the spiny dogfish shark. Both in vivo and in control saline perfusions containing 350 mmol L−1 urea, calculated intracellular urea concentrations in gill epithelial cells were close to extracellular concentrations. Urea efflux to the external water fell only non-significantly, and calculated gill intracellular urea concentration did not change when perfusate urea concentration was reduced from 350 to 175 mmol L−1 with osmotic compensation by 175 mmol L−1 mannitol. However, when the urea analogues thiourea or acetamide were present in the perfusate at concentrations equimolar (175 mmol L−1) to those of urea (175 mmol L−1), urea efflux rates were increased 4-fold and 6.5-fold respectively, and calculated gill intracellular urea concentrations were depressed by about 55%. Analogue efflux rates were similar to urea efflux rates. Previous studies have argued that either the basolateral or apical membranes provided the limiting permeability barrier, and/or that a back-transporter on the basolateral membranes of gill cells is responsible for urea retention. The present results provide new evidence that the apical membrane is the limiting factor in maintaining gill urea impermeability, and raise the prospect that a urea back-transporter, which can be competitively inhibited by thiourea and acetamide, operates at the apical membrane.