Ecosystem services, well‐being benefits and urbanization associations in a Small Island Developing State

1. Urbanization is a key driver of social and environmental change world‐wide. However, our understanding of its impacts on the multidimensional well‐being benefits that people obtain from ecosystems remains limited. 2. We explored how the well‐being contributions from land‐ and seascapes varied with urbanization level in the Solomon Islands, a fast‐urbanizing Small Island Developing State. Drawing on the social well‐being framework, we compared perceived well‐being benefits derived from ecosystem services in paired urban and rural sites. 3. Our analysis of 200 semi‐structured interviews revealed complex associations between provisioning, regulating and cultural services and well‐being benefits, with all ecosystem services contributing to material, relational and subjective well‐being dimensions. 4. Although patterns of associations between ecosystem services and well‐being benefits were similar between urban and rural dwellers, urban dwellers reported significantly fewer material, relational and subjective well‐being benefits. The most important differences between urban and rural dwellers were in terms of meeting basic material needs (e.g. income and material comfort), feeling connected to nature and feeling happy and satisfied. 5. With urbanization, livelihood activities transition from being subsistence‐based to income‐generating, which is also associated with increased wealth in urban areas. Similar to the relationship between ecosystem service well‐being benefits and urbanization, material wealth was negatively associated with perceptions of well‐being benefits. People with less material wealth appeared more reliant on nature for their multidimensional well‐being. 6. Our findings demonstrate that the altered human–nature relationships in urban areas are associated with decreases in multidimensional well‐being that people derive from nature. Improving access to particular ecosystem services, which make clear contributions to multidimensional well‐being, could be a focus for urban planners and environmental management where enhanced human–nature relationships and poverty alleviation are central goals

KOtBu : a privileged reagent for electron transfer reactions?

Many recent studies have used KOtBu in organic reactions that involve single electron transfer; in the literature, the electron transfer is proposed to occur either directly from the metal alkoxide or indirectly, following reaction of the alkoxide with a solvent or additive. These reaction classes include coupling reactions of halobenzenes and arenes, reductive cleavages of dithianes and SRN1 reactions. Direct electron transfer would imply that alkali metal alkoxides are willing partners in these electron transfer reactions, but the literature reports provide little or no experimental evidence for this. This paper examines each of these classes of reaction in turn, and contests the roles proposed for KOtBu; instead, it provides new mechanistic information that in each case supports the in situ formation of organic electron donors. We go on to show that direct electron transfer from KOtBu can however occur in appropriate cases, where the electron acceptor has a reduction potential near the oxidation potential of KOtBu, and the example that we use is CBr4. In this case, computational results support electrochemical data in backing a direct electron transfer reaction

Electron transfer reactions : KOtBu (but not NaOtBu) photoreduces benzophenone under activation by visible light

Long-standing controversial reports of electron transfer from KOtBu to benzophenone have been investigated and resolved. The mismatch in the oxidation potential of KOtBu (+0.10 V vs SCE in DMF) and the first reduction potential of benzophenone (of many values cited in the literature, the least negative value is −1.31 V vs SCE in DMF), preclude direct electron transfer. Experimental and computational results now establish that a complex is formed between the two reagents, with the potassium ion providing the linkage, which markedly shifts the absorption spectrum to provide a tail in the visible light region. Photoactivation at room temperature by irradiation at defined wavelength (365 or 400 nm), or even by winter daylight, leads to the development of the blue color of the potassium salt of benzophenone ketyl, whereas no reaction is observed when the reaction mixture is maintained in darkness. So, no electron transfer occurs in the ground state. However, when photoexcited, electron transfer occurs within a complex formed from benzophenone and KOtBu. TDDFT studies match experimental findings and also define the electronic transition within the complex as n → π*, originating on the butoxide oxygen. Computation and experiment also align in showing that this reaction is selective for KOtBu; no such effect occurs with NaOtBu, providing the first case where such alkali metal ion selectivity is rationalized in detail. Chemical evidence is provided for the photoactivated electron transfer from KOtBu to benzophenone: tert-butoxyl radicals are formed and undergo fragmentation to form (acetone and) methyl radicals, some of which are trapped by benzophenone. Likewise, when KOC(Et)3 is used in place of KOtBu, then ethylation of benzophenone is seen. Further evidence of electron transfer was seen when the reaction was conducted in benzene, in the presence of p-iodotoluene; this triggered BHAS coupling to form 4-methylbiphenyl in 74% yield

Direct Imine Acylation for Molecular Diversity in Heterocyclic Synthesis

Imines and carboxylic acids have been directly coupled using propylphosphonic acid anhydride and NEt­(<i>i</i>-Pr)₂ to give <i>N</i>-acyliminium ions, which were intramolecularly trapped with oxygen, nitrogen, sulfur, and carbon nucleophiles to provide a wide range of structurally diverse heterocycles

Synthesis of Prostaglandin Analogues, Latanoprost and Bimatoprost, Using Organocatalysis via a Key Bicyclic Enal Intermediate

Two antiglaucoma drugs, bimatoprost and latanoprost, which are analogues of the prostaglandin, PGF_2α, have been synthesized in just 7 and 8 steps, respectively. The syntheses employ an organocatalytic aldol reaction that converts succinaldehyde into a key bicyclic enal intermediate, which is primed for attachment of the required lower and upper side chains. By utilizing the crystalline lactone, the drug molecules were prepared in >99% <i>ee</i>

Electron Transfer Reactions: KO<i>t</i>Bu (but not NaO<i>t</i>Bu) Photoreduces Benzophenone under Activation by Visible Light

Long-standing controversial reports of electron transfer from KO<i>t</i>Bu to benzophenone have been investigated and resolved. The mismatch in the oxidation potential of KO<i>t</i>Bu (+0.10 V vs SCE in DMF) and the first reduction potential of benzophenone (of many values cited in the literature, the least negative value is −1.31 V vs SCE in DMF), preclude direct electron transfer. Experimental and computational results now establish that a complex is formed between the two reagents, with the potassium ion providing the linkage, which markedly shifts the absorption spectrum to provide a tail in the visible light region. Photoactivation at room temperature by irradiation at defined wavelength (365 or 400 nm), or even by winter daylight, leads to the development of the blue color of the potassium salt of benzophenone ketyl, whereas no reaction is observed when the reaction mixture is maintained in darkness. So, <i>no</i> electron transfer occurs in the ground state. However, when photoexcited, electron transfer occurs within a complex formed from benzophenone and KO<i>t</i>Bu. TDDFT studies match experimental findings and also define the electronic transition within the complex as n → π*, originating on the butoxide oxygen. Computation and experiment also align in showing that this reaction is selective for KO<i>t</i>Bu; no such effect occurs with NaO<i>t</i>Bu, providing the first case where such alkali metal ion selectivity is rationalized in detail. Chemical evidence is provided for the photoactivated electron transfer from KO<i>t</i>Bu to benzophenone: <i>tert</i>-butoxyl radicals are formed and undergo fragmentation to form (acetone and) methyl radicals, some of which are trapped by benzophenone. Likewise, when KOC­(Et)₃ is used in place of KO<i>t</i>Bu, then ethylation of benzophenone is seen. Further evidence of electron transfer was seen when the reaction was conducted in benzene, in the presence of <i>p-</i>iodotoluene; this triggered BHAS coupling to form 4-methylbiphenyl in 74% yield

KO<i>t</i>Bu: A Privileged Reagent for Electron Transfer Reactions?

Many recent studies have used KO<i>t</i>Bu in organic reactions that involve single electron transfer; in the literature, the electron transfer is proposed to occur either directly from the metal alkoxide or indirectly, following reaction of the alkoxide with a solvent or additive. These reaction classes include coupling reactions of halobenzenes and arenes, reductive cleavages of dithianes, and S_RN1 reactions. Direct electron transfer would imply that alkali metal alkoxides are willing partners in these electron transfer reactions, but the literature reports provide little or no experimental evidence for this. This paper examines each of these classes of reaction in turn, and contests the roles proposed for KO<i>t</i>Bu; instead, it provides new mechanistic information that in each case supports the <i>in situ</i> formation of organic electron donors. We go on to show that direct electron transfer from KO<i>t</i>Bu can however occur in appropriate cases, where the electron acceptor has a reduction potential near the oxidation potential of KO<i>t</i>Bu, and the example that we use is CBr₄. In this case, computational results support electrochemical data in backing a direct electron transfer reaction