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Consistent sociality but flexible social associations across temporal and spatial foraging contexts in a colonial breeder 期刊论文
ECOLOGY LETTERS, 2020, 23 (7) : 1085-1096
作者:  Jones, Teri B.;  Green, Jonathan A.;  Patrick, Samantha C.;  Evans, Julian C.;  Wells, Melanie R.;  Rodriguez-Malagon, Marlenne A.;  Arnould, John P. Y.
收藏  |  浏览/下载：18/0  |  提交时间：2020/05/13
Coloniality  consistency  group formation  individual behaviour  multiplex networks  social flexibility  social foraging  sociality  seabirds  
Ruthenium isotope vestige of Earth's pre-late-veneer mantle preserved in Archaean rocks 期刊论文
NATURE, 2020, 579 (7798) : 240-+
作者:  Abadie, Valerie;  Kim, Sangman M.;  Lejeune, Thomas;  Palanski, Brad A.;  Ernest, Jordan D.;  Tastet, Olivier;  Voisine, Jordan;  Discepolo, Valentina;  Marietta, Eric, V;  Hawash, Mohamed B. F.;  Ciszewski, Cezary;  Bouziat, Romain;  Panigrahi, Kaushik;  Horwath, Irina;  Zurenski, Matthew A.;  Lawrence, Ian;  Dumaine, Anne;  Yotova, Vania;  Grenier, Jean-Christophe;  Murray, Joseph A.;  Khosla, Chaitan;  Barreiro, Luis B.;  Jabri, Bana
收藏  |  浏览/下载：41/0  |  提交时间：2020/05/13

The accretion of volatile-rich material from the outer Solar System represents a crucial prerequisite for Earth to develop oceans and become a habitable planet(1-4). However, the timing of this accretion remains controversial(5-8). It has been proposed that volatile elements were added to Earth by the late accretion of a late veneer consisting of carbonaceous-chondrite-like material after core formation had ceased(6,9,10). This view could not be reconciled with the ruthenium (Ru) isotope composition of carbonaceous chondrites(5,11), which is distinct from that of the modern mantle(12), or of any known meteorite group(5). As a possible solution, Earth'  s pre-late-veneer mantle could already have contained a fraction of Ru that was not fully extracted by core formation(13). The presence of such pre-late-veneer Ru can only be established if its isotope composition is distinct from that of the modern mantle. Here we report the first high-precision, mass-independent Ru isotope compositions for Eoarchaean ultramafic rocks from southwest Greenland, which display a relative Ru-100 excess of 22 parts per million compared with the modern mantle value. This Ru-100 excess indicates that the source of the Eoarchaean rocks already contained a substantial fraction of Ru before the accretion of the late veneer. By 3.7 billion years ago, the mantle beneath southwest Greenland had not yet fully equilibrated with late accreted material. Otherwise, no Ru isotopic difference relative to the modern mantle would be observed. If constraints from other highly siderophile elements besides Ru are also considered(14), the composition of the modern mantle can only be reconciled if the late veneer contained substantial amounts of carbonaceous-chondrite-like materials with their characteristic Ru-100 deficits. These data therefore relax previous constraints on the late veneer and are consistent with volatile-rich material from the outer Solar System being delivered to Earth during late accretion.


  
Late-stage oxidative C(sp(3))-H methylation 期刊论文
NATURE, 2020, 580 (7805) : 621-+
作者:  Fessler, Evelyn;  Eckl, Eva-Maria;  Schmitt, Sabine;  Mancilla, Igor Alves;  Meyer-Bender, Matthias F.;  Hanf, Monika;  Philippou-Massier, Julia;  Krebs, Stefan;  Zischka, Hans;  Jae, Lucas T.
收藏  |  浏览/下载：69/0  |  提交时间：2020/07/03

Frequently referred to as the '  magic methyl effect'  , the installation of methyl groups-especially adjacent (alpha) to heteroatoms-has been shown to dramatically increase the potency of biologically active molecules(1-3). However, existing methylation methods show limited scope and have not been demonstrated in complex settings(1). Here we report a regioselective and chemoselective oxidative C(sp(3))-H methylation method that is compatible with late-stage functionalization of drug scaffolds and natural products. This combines a highly site-selective and chemoselective C-H hydroxylation with a mild, functional-group-tolerant methylation. Using a small-molecule manganese catalyst, Mn(CF3PDP), at low loading (at a substrate/catalyst ratio of 200) affords targeted C-H hydroxylation on heterocyclic cores, while preserving electron-neutral and electron-rich aryls. Fluorine- or Lewis-acid-assisted formation of reactive iminium or oxonium intermediates enables the use of a mildly nucleophilic organoaluminium methylating reagent that preserves other electrophilic functionalities on the substrate. We show this late-stage C(sp(3))-H methylation on 41 substrates housing 16 different medicinally important cores that include electron-rich aryls, heterocycles, carbonyls and amines. Eighteen pharmacologically relevant molecules with competing sites-including drugs (for example, tedizolid) and natural products-are methylated site-selectively at the most electron rich, least sterically hindered position. We demonstrate the syntheses of two magic methyl substrates-an inverse agonist for the nuclear receptor RORc and an antagonist of the sphingosine-1-phosphate receptor-1-via late-stage methylation from the drug or its advanced precursor. We also show a remote methylation of the B-ring carbocycle of an abiraterone analogue. The ability to methylate such complex molecules at late stages will reduce synthetic effort and thereby expedite broader exploration of the magic methyl effect in pursuit of new small-molecule therapeutics and chemical probes.


A manganese-catalysed oxidative C(sp(3))-H methylation method allows a methyl group to be selectively installed into medicinally important heterocycles, providing a way to improve pharmaceuticals and better understand the '  magic methyl effect'  .