Directed carbonylative (3+1+2) cycloadditions of amino-substituted cyclopropanes and alkynes: reaction development and increased efficiencies using a cationic rhodium system

AbstractUrea-directed carbonylative insertion of Rh(I)-catalysts into one of the two proximal C–C bonds of aminocyclopropanes generates rhodacyclopentanone intermediates. These are trapped by N-tethered alkynes to provide a (3+1+2) cycloaddition protocol that accesses N-heterobicyclic enones. Stoichiometric studies on a series of model rhodacyclopentanone complexes outline key structural features and provide a rationale for the efficacy of urea directing groups. A comprehensive evaluation of cycloaddition scope and a ‘second generation’ cationic Rh(I)-system, which provides enhanced yields and reaction rates for challenging substrates, are presented

New Initiation Modes for Directed Carbonylative C-C Bond Activation:Rhodium-Catalyzed (3+1+2) Cycloadditions of Aminomethylcyclopropanes

Under carbonylative conditions, neutral Rh­(I)-systems modified with weak donor ligands (AsPh₃ or 1,4-oxathiane) undergo N-Cbz, N-benzoyl, or N-Ts directed insertion into the proximal C–C bond of amino­methyl­cyclo­propanes to generate rhodacyclo­pentanone intermediates. These are trapped by N-tethered alkenes to provide complex perhydroisoindoles

Modular access to substituted azocanes via a rhodium-catalyzed cycloaddition-fragmentation strategy

A short entry to substituted azocanes by a Rh-catalyzed cycloaddition–fragmentation process is described. Specifically, exposure of diverse <i>N</i>-cyclopropylacrylamides to phosphine-ligated cationic Rh­(I) catalyst systems under a CO atmosphere enables the directed generation of rhodacyclopentanone intermediates. Subsequent insertion of the alkene component is followed by fragmentation to give the heterocyclic target. Stereochemical studies show, for the first time, that alkene insertion into rhodacyclopentanones can be reversible

BIMP‐Catalyzed 1,3‐Prototropic Shift for the Highly Enantioselective Synthesis of Conjugated Cyclohexenones

A bifunctional iminophosphorane (BIMP)‐catalysed enantioselective synthesis of α,β‐unsaturated cyclohexenones through a facially selective 1,3‐prototropic shift of β,γ‐unsaturated prochiral isomers, under mild reaction conditions and in short reaction times, on a range of structurally diverse substrates, is reported. α,β‐Unsaturated cyclohexenone products primed for downstream derivatisation were obtained in high yields (up to 99 %) and consistently high enantioselectivity (up to 99 % ee). Computational studies into the reaction mechanism and origins of enantioselectivity, including multivariate linear regression of TS energy, were carried out and the obtained data were found to be in good agreement with experimental findings

Antinuclear Antibodies, Rheumatoid Factor and c-Reactive Protein in Serum of Normal Women Using Oral Contraceptives

Some women who report to a hospital or arthritis clinic note exacerbation of rheumatic complaints and develop serologic abnormalities while taking oral contraceptives. The current study concerns the detection of antinuclear antibodies, rheumatoid factor and C-reactive protein in normal women using these drugs. Prospective study of 82 women before and during oral contraceptive use permitted the detection of 4 who developed antinuclear antibodies, 9 who developed rheumatoid factor and 30 who developed C-reactive protein after less than 1 year of drug use. The prevalence of positive tests was greater in a group of 210 women who were using OC than that found in a group of 174 who had never used these drugs. None of these women developed rheumatic symptoms while using oral contraceptives.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/37718/1/1780140208_ftp.pd

Training future generations to deliver evidence-based conservation and ecosystem management

1. To be effective, the next generation of conservation practitioners and managers need to be critical thinkers with a deep understanding of how to make evidence-based decisions and of the value of evidence synthesis. 2. If, as educators, we do not make these priorities a core part of what we teach, we are failing to prepare our students to make an effective contribution to conservation practice. 3. To help overcome this problem we have created open access online teaching materials in multiple languages that are stored in Applied Ecology Resources. So far, 117 educators from 23 countries have acknowledged the importance of this and are already teaching or about to teach skills in appraising or using evidence in conservation decision-making. This includes 145 undergraduate, postgraduate or professional development courses. 4. We call for wider teaching of the tools and skills that facilitate evidence-based conservation and also suggest that providing online teaching materials in multiple languages could be beneficial for improving global understanding of other subject areas.Peer reviewe

A communal catalogue reveals Earth's multiscale microbial diversity

Our growing awareness of the microbial world's importance and diversity contrasts starkly with our limited understanding of its fundamental structure. Despite recent advances in DNA sequencing, a lack of standardized protocols and common analytical frameworks impedes comparisons among studies, hindering the development of global inferences about microbial life on Earth. Here we present a meta-analysis of microbial community samples collected by hundreds of researchers for the Earth Microbiome Project. Coordinated protocols and new analytical methods, particularly the use of exact sequences instead of clustered operational taxonomic units, enable bacterial and archaeal ribosomal RNA gene sequences to be followed across multiple studies and allow us to explore patterns of diversity at an unprecedented scale. The result is both a reference database giving global context to DNA sequence data and a framework for incorporating data from future studies, fostering increasingly complete characterization of Earth's microbial diversity.Peer reviewe

A communal catalogue reveals Earth’s multiscale microbial diversity

Our growing awareness of the microbial world’s importance and diversity contrasts starkly with our limited understanding of its fundamental structure. Despite recent advances in DNA sequencing, a lack of standardized protocols and common analytical frameworks impedes comparisons among studies, hindering the development of global inferences about microbial life on Earth. Here we present a meta-analysis of microbial community samples collected by hundreds of researchers for the Earth Microbiome Project. Coordinated protocols and new analytical methods, particularly the use of exact sequences instead of clustered operational taxonomic units, enable bacterial and archaeal ribosomal RNA gene sequences to be followed across multiple studies and allow us to explore patterns of diversity at an unprecedented scale. The result is both a reference database giving global context to DNA sequence data and a framework for incorporating data from future studies, fostering increasingly complete characterization of Earth’s microbial diversity

Use of Renewable Resources Towards the Sustainable Production of Crop Protection Agents

Today, the production of food accounts for roughly one quarter of the anthropogenic greenhouse gas emissions. Since the 1970s, thanks to substantial research and development, the overall yield output in farm fields has increased by ca. 60%, while the net use of crop protection agents per square meter of farm field has been reduced by more than 90%. The development of modern crop protection agents remains an important need as new pests, diseases and weeds continue to affect crops. The vast majority of these effective solutions are manufactured using raw materials that ultimately come from fossil resources. In this article, we are touring within the agrochemical landscape to provide the reader with an overview of concrete examples on how in this industrial field, renewable and sustainable raw materials have been used to produce active ingredients. We are also discussing the opportunities for future development as well as some of the challenges and needs that are emerging

Diastereoselective SmI2 mediated cascade radical cyclisations of methylenecyclopropane derivatives - syntheses of paeonilactone B and 6-epi-paeonilactone A

The SmI2 mediated cascade cyclisations of several methylenecyclopropyl ketones have been examined and found to proceed with high diastereoselectivity, which is critically dependent on the presence of HMPA in the reaction. In one case the radical species at the end of the cascade sequence underwent an unexpected and highly stereoselective dimerisation. The cascade methodology has been applied to a short synthesis of (+/-)-paeonilactone B and of (+/-)-6-epi-paeonilactone A