Search

Cross-electrophile coupling reactions have evolved into a major strategy for rapidly assembling important molecules, yet challenges remain for the formation of C(sp3)–C(sp3) bonds that form the core of nearly all organic compounds. Herein, we report a distinct, transition metal-free platform to form such bonds without the need for activating or stabilizing groups on the coupling partners. The reaction is enabled by an unusual single electron transfer in a frustrated ion pair and is complementary in terms of scope to transition metal-catalyzed processes. Moreover, we could further leverage this new mechanistic manifold in the design of other reactions, showing the broad potential of this new reactivity in organic synthesis.

A rhodium-catalyzed anti-Markovnikov hydroiodination of aromatic and aliphatic terminal alkynes is reported. Depending on the choice of ligand and substrate, either (E)- or (Z)-configured alkenyl iodides are obtained in high to exclusive isomeric purity. The reaction exhibits a broad substrate scope and high functional group tolerance, employing easily accessible or commercially available aliphatic iodides as HI surrogates through a shuttle process. The synthesized vinyl iodides were applied in several C-C and C-heteroatom bond-forming reactions with full retention of the stereoselectivity. The developed method could be used to significantly shorten the total synthesis of a marine cis-fatty acid. Additionally, initial deuterium-labeling experiments and stoichiometric reactions shed some light on the potential reaction mechanism., Angewandte Chemie. International Edition, 62 (4), ISSN:1433-7851, ISSN:1521-3773, ISSN:0570-0833

A method for the nucleophilic fluorination of heptamethyl aryl trisiloxanes to form fluoroarenes is reported. The reaction proceeds in the presence of Cu(OTf)(2) and KHF(2) as the fluoride source under mild conditions for a broad range of heptamethyltrisiloxyarenes with high functional group tolerance. The combination of this method with the silylation of aryl C–H bonds enables the regioselective fluorination of non-activated arenes controlled by steric effects following a two-step protocol.

We report an efficient and broadly applicable palladium‐catalyzed iodination of inexpensive and abundant aryl and vinyl carboxylic acids via in situ activation to the acid chloride and formation of a phosphonium salt. The use of 1‐iodobutane as iodide source in combination with a base and a deoxychlorinating reagent gives access to a wide range of aryl and vinyl iodides under Pd/Xantphos catalysis, including complex drug‐like scaffolds. Stoichiometric experiments and kinetic analysis suggest a unique mechanism involving C−P reductive elimination to form the Xantphos phosphonium chloride, which subsequently initiates an unusual halogen exchange by outer sphere nucleophilic substitution., An efficient and broadly applicable palladium‐catalyzed iodination of inexpensive and abundant aryl and vinyl carboxylic acids via in situ activation to the acid chloride and formation of a phosphonium salt was developed. The use of 1‐iodobutane as iodide source in combination with a base and a deoxychlorinating reagent gives access to a wide range of aryl and vinyl iodides under Pd/Xantphos catalysis.

We describe a new functional group metathesis between aryl nitriles and aryl thioethers. The catalytic system nickel/dcype is essential to achieve this fully reversible transformation in good to excellent yields. Furthermore, the cyanide- and thiol-free reaction shows high functional group tolerance and great efficiency for the late-stage derivatization of commercial molecules. Finally, synthetic applications demonstrate its versatility and utility in multistep synthesis. ISSN:0002-7863 ISSN:1520-5126

We report stereodivergent allylic substitution reactions of allylic esters with prochiral enolates derived from azaaryl acetamides and acetates to form products from addition of the enolates at the most substituted carbon of an allyl moiety with two catalysts, a chiral metallacyclic iridium complex and a chiral bisphosphine-ligated copper(I) complex, which individually control the configuration of the electrophilic and nucleophilic carbon atoms, respectively. By simple permutations of enantiomers of the two catalysts, all four stereoisomers of products containing two stereogenic centers were synthesized individually with high diastereoselectivity and enantioselectivity. A variety of azaaryl acetamides and acetates bearing pyridyl, benzothiazolyl, benzoxazolyl, pyrazinyl, quinolinyl and isoquinolinyl moieties were all found to be suitable for this transformation.

Recent advances in the development of attosecond soft x-ray sources toward photon wavelengths below 10 nm are also driving the development of suited broadband multilayer optics for steering and shaping attosecond pulses. We demonstrate that current attosecond experiments in the sub-200-eV range benefit from these improved optics. We present our achievements in utilizing ion-beam-deposited chromium/scandium (Cr/Sc) multilayer mirrors, optimized by tailored material dependent deposition and interface polishing, for the generation of single attosecond pulses from a high-harmonic cut-off spectrum at a central energy of 145 eV. Isolated attosecond pulses have been measured by soft x-ray-pump/NIR-probe electron streaking experiments and characterized using frequency-resolved optical gating for complete reconstruction of attosecond bursts (FROG/CRAB). The results demonstrate that Cr/Sc multilayer mirrors can be used as efficient attosecond optics for reflecting 600-attosecond pulses at a photon energy of 145 eV, which is a prerequisite for present and future attosecond experiments in this energy range.

(2002). Interview between Manfred Heid, Director of the Goethe-Institute Inter Nationes Chicago and Philip Boehm. Translation Review: Vol. 63, No. 1, pp. 71-74.

An everyday sort of earthquake had caused the sapphire bottle of cholesterol-free mineral water from the Scottish highlands, which welcomed you to your suite at the Beverly Hilton along with compliments of the management, to vibrate off the nightstand and shatter against the marble base of the floor lamp, foiling your designs for yesterday evening. With a pained groan you rolled over onto your side-always the right-of the amusingly named king-size bed in order to call Mom in Santa Monica: "Are you okay?" Your attempts at a cover-up were easily thwarted: after all, it was safe to assume the light tremors weren't felt too far outside Los Angeles, and even in the age of CNN, news of something impossible to predict necessarily had to arrive after the actual event. What else could you do but admit you were in town three days sooner than expected? Because we had to take off first thing in the morning. "That's right, WE!" To Johannesburg. No not Africa, don't be silly: it's halfway to Las Vegas. No it's family business, not business business. Her memory was not deceiving her, she was the closest relative you had, and the last one left as well-it has to do with Florian. "You know very well who that is, Mom!" On account of his father. It's a funeral not a party. "He died, that's right!" Even before you could end the conversation ("If you'd like to... Of course I think it's appropriate!") with an "All right, see you soon!" it was clear what was coming: "My mother wants to meet you!" Her persistent refusal to meet or even acknowledge me, which had caused you seven years of pain, had never really bothered me, except to make me sorry for your sake. After all she was an old lady raised in a different world, under the Kaiser-what purpose would it serve to make her fragile heart bear one burden more? But now that I was finally going to meet her, I was excited to find out exactly who this person was, this woman capable of reducing you to a few pitiful excuses, and so much so that you coated yourself in a tar-like silence, which didn't become you at all, as the traffic shoved us from one signal to the next, while we rode our rented wheels from the land of the rising sun down the boulevard of the setting one, towards the giant, blindingly lit sign hawking California oranges at the end of the asphalted world. "You don't mean to tell me you're still running around in those Asian nightshirts!" A gray-haired lady in a white nurse's uniform had opened the door to one of the look-alike houses that fronted one of the look-alike lawns of saturated green (so perfect I had to convince myself it wasn't Astroturf) on one of the look-alike streets in quiet, upscale Brentwood Park. Her black face was beaming as she greeted you like a long-lost brother, then led us ("Bring them in, Nancy!") into a dimly lit room where clouds of Chanel No. 5 battled a lingering odor of Lysol. Now we were standing in front of a tiny old woman who looked as lost as a child in the overly large hospital bed, but who was sitting very erect, sizing you up reproachfully, her face a shiny lump of greased dough stuck with a pair of big dark raisins, until at last she allowed you to bend over and embrace her. She was wearing a cream-colored, quilted bed jacket and a kind of turban made of purple crushed silk, which instead of evoking a dancer's ageless rigor, as intended, made her look more like a down. "So you're the little boy who's turned my son's head-come closer, it's not every day I get to feast my old eyes on so much beauty!" I could have kissed her, but all I dared do as I presented my hand was make a little bow that felt more mannered than polite. "Mon dieu, a cavalier, he can't have that from you, Peter; tell Nancy she can put the flowers you didn't bring me in the vase she broke yesterday-and you sit down right here, we have a lot to talk about, the two of us!" Apart from a small dressing table from her days as a movie makeup artist, and the wide-screened television resting on top of it, the room was accoutered only with shadows; before I had a chance to find a chair she had grabbed my arm and planted me on the edge of her bed. …

It turns out that what gets debated in the media actually does leave its mark in real life?a minor miracle I just discovered. First the media launch an exchange on a specific topic or issue, with serious papers tackling serious problems such as "The Societal Ramifications of Xenophobia," and less serious papers taking on less serious matters such as "How to Lose Ten Pounds in Ten Days" or things like that. The topic is then subjected to a thorough debate.. .which means there have to be at least two contrasting opinions, such as "Xenophobia is best reduced by reducing the number of foreigners," as opposed to "Xenophobia is best reduced by revising the image of the foreigner in the collective consciousness, which could be completely repro grammed by enlisting the media to help shift the hostility away from foreigners and on to, say, venture capitalists." The "weight debate" follows a similar pattern, since you can re duce your weight by natural or artificial means?i.e., Low Carbo Diet versus Liposuction. Each controversy runs for about two weeks before it's pulled from the paper and replaced with some new hot topic. The discussions don't solve anything, but they do leave their mark. For some time the big issue was Hostility Toward Foreigners, and out of nowhere a feel ing of togetherness emerged among people who didn't necessarily belong together, and who might have even resisted such a grouping in the past: Arabs, Jews, Turks, Chinese?all because they were the Foreigners on the receiving end of the Hostility. Here's an example from real life: a Russian theater, the Nostalgia, decided to try Pushkin's "Mozart and Salieri." My friend the actor from Smolensk was cast as the evil, depressed composer Salieri, who at the end of the tragedy poisons Mozart out of envy and frustration. In reality my friend is just a plain nice guy who's been married to a

For years my relationship with Malina consisted of awkward meetings, absolute follies, and the biggest possible misunderstandings I mean of course much greater misunderstandings than with other people. Certainly I was subordinate to him from the beginning, and I must have known early on that he was destined to be my doom, that Malina's place was already occupied by Malina even before he entered my life. I was only spared or perhaps I spared myself meeting him too soon, for there were numerous occasions at the E 2 and H 2 streetcar stop by the Stadtpark when something could have, and almost did, happen. There he stood holding a newspaper; I acted as if I didn't see him, although I kept staring over my paper in his direction, without flinching. I couldn't tell whether he was really so engrossed in the news or whether he had noticed my pinning him, hypnotizing him, wanting to force him to look up. Me forcing him! I thought: if the E 2 comes first, everything will be fine; but heaven forbid the unfriendly H 2 or the even rarer G 2 should arrive before. Finally the E 2 did indeed pull up, but by the time I had jumped onto the second car Malina had vanished: he wasn't to be found in the first car or in my own and he hadn't remained behind. He must have dashed into the train station as I had