22 Apr 09:12

Цитата #427845

из паблика муз.лэйбла:
"Лучше играть дум метал и умереть неизвестным, чем просто умереть неизвестным"
22 Apr 12:20

Transition-Metal-Free BF3-Mediated Oxidative and Non-Oxidative Cross-Coupling of Pyridines

by Quan Chen, Thierry León, Paul Knochel

Abstract

We report a BF3-mediated direct alkynylation of pyridines at C(2) by using a variety of alkynyllithium reagents (oxidative cross-coupling). Moreover, we have developed a novel transition-metal-free cross-coupling method between alkylmagnesium reagents and 4-substituted pyridines, such as isonicotinonitrile and 4-chloropyridine, by employing BF3⋅OEt2 as a promoter. The combination of these methods enabled us to efficiently prepare a range of di-, tri-, and tetrasubstituted pyridines.

Thumbnail image of graphical abstract

Oxidative or non-oxidative—That is the question! Pyridines bearing a substituent at position 4 readily undergo a BF3-mediated oxidative coupling at position 2 with a wide range of alkynyllithium compounds. In contrast, 4-cyano- or 4-chloropyridines undergo a novel BF3-mediated cross-coupling at position 4 with alkylmagnesium reagents. The combination of the two transition-metal-free procedures allows the preparation of a broad range of pyridines.

22 Apr 12:20

Stereocontrolled Synthesis of Adjacent Acyclic Quaternary-Tertiary Motifs: Application to a Concise Total Synthesis of (−)-Filiformin

by Daniel J. Blair, Catherine J. Fletcher, Katherine M. P. Wheelhouse, Varinder K. Aggarwal

Abstract

Lithiation/borylation methodology has been developed for the synthesis of acyclic quaternary-tertiary motifs with full control of relative and absolute stereochemistry, thus leading to all four possible isomers of a stereodiad. A novel intramolecular Zweifel-type olefination enabled acyclic stereocontrol to be transformed into cyclic stereocontrol. These key steps have been applied to the shortest enantioselective synthesis of (−)-filiformin to date (9 steps) with full stereocontrol.

Thumbnail image of graphical abstract

True to (fili)form: Lithiation/borylation methodology has been developed for the synthesis of acyclic quaternary-tertiary motifs with full control of relative and absolute stereochemistry, thus leading to all four possible isomers of a stereodiad. A novel intramolecular Zweifel-type olefination enabled acyclic stereocontrol to be transformed into cyclic stereocontrol. These key steps were applied to the enantioselective synthesis of (−)-filiformin.

22 Apr 10:14

Single Electron Transfer in Radical Ion and Radical-Mediated Organic, Materials and Polymer Synthesis

by Na Zhang, Shampa R. Samanta, Brad M. Rosen and Virgil Percec

TOC Graphic

Chemical Reviews
DOI: 10.1021/cr400689s
22 Apr 15:36

ralphthemouth: lady—hulk: It just keeps…… getting. …. better



ralphthemouth:

lady—hulk:

It just keeps…… getting. …. better

22 Apr 15:42

virused: list of people i like: dogs

virused:

list of people i like:

  1. dogs
22 Apr 04:00

April 22, 2014


22 Apr 04:00

April 22, 2014


22 Apr 12:37

Oxidative Dehydrogenative Couplings of Pyrazol-5-amines Selectively Forming Azopyrroles

by Bo Jiang, Yi Ning, Wei Fan, Shu-Jiang Tu and Guigen Li

TOC Graphic

The Journal of Organic Chemistry
DOI: 10.1021/jo5004967
22 Apr 18:01

Colorful Layers of Paper Form Intricate Sculptures and Patterns

by Jenny Zhang

Paris-based designer Maud Vantours is a master at constructing incredible 3D sculptures and mesmerizing patterns out of paper. After carefully cutting out assorted shapes, she meticulously builds up layer upon layer, superimposing the papers to create intricate and colorful works of art. Her paper works range from geometric patterns to dizzying spirals to delicately crafted flowers. With amazing texture, elaborate detail, and vibrant colors, each piece is a joy to look at.

Although Vantours graduated from the Parisian school Duperré with a specialization in textiles and design, her favorite medium is paper because the works can "transcend a simple material and transform it into a work of art." She says, "I love to create original graphics with multicolored and dreamlike landscapes."












Maud Vantours Website
via [Dark Silence in Suburbia]
22 Apr 19:00

Improve Your Resume with This Simple Formula Recommended by Google

by Melanie Pinola

Improve Your Resume with This Simple Formula Recommended by Google

Recruiters don't look at your resume for more than a few precious seconds , but that doesn't mean you shouldn't still carefully craft your resume to make sure you've got the best chances of landing a job. Here's a simple formula from Google's HR chief that'll help you put the best information on your resume.

Read more...








22 Apr 14:58

Different Reactivity of the Various Platinum Oxides and Chemisorbed Oxygen in CO Oxidation on Pt(111)

by Daniel Miller, Hernan Sanchez Casalongue, Hendrik Bluhm, Hirohito Ogasawara, Anders Nilsson and Sarp Kaya

TOC Graphic

Journal of the American Chemical Society
DOI: 10.1021/ja413125q
22 Apr 20:20

PERO NO LO HICISTE - Una de las tantas historias que quedan tapadas por la guerra


22 Apr 21:45

scotch & jazz @ dusk

by joenagle
22 Apr 18:25

Palladium-Catalyzed Direct Dehydrogenative Annulation of Ferrocenecarboxamides with Alkynes in Air

by Wucheng Xie, Bin Li, Shansheng Xu, Haibin Song and Baiquan Wang

TOC Graphic

Organometallics
DOI: 10.1021/om5002606
23 Apr 04:20

Mmmmnope. [pbs]





Mmmmnope. [pbs]

23 Apr 02:30

Doge.



Doge.

23 Apr 00:00

Phone Alarm

Who's calling me?? WHY IS THE WORST PERSON IN THE WORLD CALLING ME!?
23 Apr 02:35

Tumblr | 132.gif

132.gif
23 Apr 02:34

Gurl Gamer | bb5.png

bb5.png
23 Apr 06:11

Цитата #427854

Настя: Ты когда-нибудь плакал? Так, чтобы по-настоящему?
Seberya: Ну да. два раза.
Настя: Только два раза? И что ты в эти моменты чувствовал?
Seberya: Ну... Ненависть. Лютую ненависть. Первый раз - к Джоффри. А во второй - к Уолдеру Фрею.
23 Apr 11:10

Sites for Methane Activation on Lithium-Doped Magnesium Oxide Surfaces

by Karolina Kwapien, Joachim Paier, Joachim Sauer, Michael Geske, Ulyana Zavyalova, Raimund Horn, Pierre Schwach, Annette Trunschke, Robert Schlögl

Abstract

Density functional calculations yield energy barriers for H abstraction by oxygen radical sites in Li-doped MgO that are much smaller (12±6 kJ mol−1) than the barriers inferred from different experimental studies (80–160 kJ mol−1). This raises further doubts that the Li+O.− site is the active site as postulated by Lunsford. From temperature-programmed oxidative coupling reactions of methane (OCM), we conclude that the same sites are responsible for the activation of CH4 on both Li-doped MgO and pure MgO catalysts. For a MgO catalyst prepared by sol–gel synthesis, the activity proved to be very different in the initial phase of the OCM reaction and in the steady state. This was accompanied by substantial morphological changes and restructuring of the terminations as transmission electron microscopy revealed. Further calculations on cluster models showed that CH4 binds heterolytically on Mg2+O2− sites at steps and corners, and that the homolytic release of methyl radicals into the gas phase will happen only in the presence of O2.

Thumbnail image of graphical abstract

The energy barriers for methane activation by hydrogen abstraction at oxygen radical sites are unrealistically low. C[BOND]H bonds can also heterolytically add onto a regular MgO ion pair at morphological defects such as steps and corners. Release of methyl radicals into the gas phase will happen only in the presence of O2.

23 Apr 00:00

04.23.2014

Cyanide and Happiness, a daily webcomic

Copy this into your blog, website, etc.
<a href="http://explosm.net/comics/3535/"><img alt="Cyanide and Happiness, a daily webcomic" src="http://www.flashasylum.com/db/files/Comics/Kris/joe.png" border=0></a><br />Cyanide & Happiness @ <a href="http://explosm.net">Explosm.net</a>

...or into a forum
[URL="http://explosm.net/comics/3535/"]
[IMG]http://www.flashasylum.com/db/files/Comics/Kris/joe.png[/IMG][/URL]
Cyanide & Happiness @ [URL="http://explosm.net/"]Explosm.net[/URL]
<—- Share this comic!

23 Apr 15:38

[revolver925]

23 Apr 16:13

avocado cup salads, two ways

by deb

avocado cup confetti salads

I have the most boring thing, ever, to tell you today (and clearly it’s not “how to write an enticing lede”): I tried not to eat bread for a couple months. Wait, come back! Let me explain. I don’t mean ever. I am not anti-carb or anti-dessert, nor is Wheat Belly our new idea of a good bedtime story; I am ever your gluten-full host. I remain certain that freshly-baked, crackly-crusted artisanal bread is one of the greatest things in the world; to turn it down a moderate serving of it when you’re able to enjoy it (chemically and all that) is a sacrilege. But that’s not really what most of our bread looks like, does it? Most often, bread is merely bookends on a sandwich, with the goal of making filling portable. Or, it’s toasted so that it can sop up butter, jam or a runny yolk, or crouton-ed to make a salad feel bulkier. It’s all too infrequently in and of itself noteworthy. These latter categories of bread were what I suspected I wouldn’t miss if when I challenged myself to skip them. That is, at least two meals a day: an ascetic, I am not.

rainbow of peppers, black beans
bell peppers, black beans, jalapeno, white onion

But I promise, I didn’t drag you here today to sell you on a refined carb-free life as I myself have little interest in living one. What I’d hoped to share was the neat thing that many less stubborn than myself have known of eons: when you tip the food scales away from lackluster bread-fill, a wonderful thing happens: vegetables, beans and protein come back into prominence, and it was just the cooking recharge that I needed. To wit, since the beginning of the year we’ve talked about eggs baked in a nest of spinach and mushrooms (biscuits on the side), a seasonal mayo-light riff on devilled eggs, my new favorite three-bean chili (a small amount of brown rice underneath), chicken fajitas loaded with vegetables, beans, slaw, pico, and guacamole (all perched on one or two small corn tortillas) and a kale-quinoa salad I’m so addicted to, if I don’t have it for lunch at least three days a week, I feel twitchy.

radishes, cucumbers, scallions

... Read the rest of avocado cup salads, two ways on smittenkitchen.com


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