共查询到20条相似文献,搜索用时 609 毫秒
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Benjamin N. Bhawal Bill Morandi 《Angewandte Chemie (International ed. in English)》2019,58(30):10074-10103
Transfer hydrogenation, alkene metathesis, and alkyne metathesis possess great value to the synthetic chemistry community. One of the key features of these processes is their reversibility, which can be attributed to the presence of the same number and type of functional groups in both the reactants and products, making these reactions isofunctional. These classic reactions have recently inspired the development of novel shuttle and metathesis reactions that offer great promise for synthetic chemistry. This Review describes and systematically categorizes both recent and older examples of shuttle and metathesis reactions other than transfer hydrogenation and alkene/alkyne metathesis. 相似文献
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The dehydrobromination and debromination reactions of some α, β-dibromosulfones in a five-membered ring with sodium phenylthiolate, pyridine, and sodium methoxide have been studied. In general, phenylthiolate induces debromination elimination reactions while pyridine and methoxide induce dehydrobromination reactions. 相似文献
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In situ generated nitro alkenes underwent tandem Michael-Henry and Michael-Michael sequences leading to the ‘one-pot’ formation of 3,4-substituted tetrahydrothiophenes using the commercially available 1,4-dithiane-2,5-diol (the dimer of mercaptoacetaldehyde) or its 4-mercapto-2-butenoates derivatives as suitable bifunctional partners, respectively. 相似文献
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Edouard Godineau Dr. Yannick Landais Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(13):3044-3055
All in one pot! Radical, radical–ionic, and radical–organometallic MCR are highly convergent processes, representing a useful pathway to molecular and structural diversity (see scheme). This concept article highlights recent developments in the field and shows the potential of the strategy for the economical elaboration of various kinds of organic substrates.
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Toward a Symphony of Reactivity: Cascades Involving Catalysis and Sigmatropic Rearrangements 下载免费PDF全文
Prof. Amanda C. Jones Prof. Jeremy A. May Prof. Richmond Sarpong Prof. Brian M. Stoltz 《Angewandte Chemie (International ed. in English)》2014,53(10):2556-2591
Catalysis and synthesis are intimately linked in modern organic chemistry. The synthesis of complex molecules is an ever evolving area of science. In many regards, the inherent beauty associated with a synthetic sequence can be linked to a certain combination of the creativity with which a sequence is designed and the overall efficiency with which the ultimate process is performed. In synthesis, as in other endeavors, beauty is very much in the eyes of the beholder. It is with this in mind that we will attempt to review an area of synthesis that has fascinated us and that we find extraordinarily beautiful, namely the combination of catalysis and sigmatropic rearrangements in consecutive and cascade sequences. 1 Sometimes the assessment of beauty is nearly unanimous. The first four notes of Beethoven’s 5th Symphony (Symphony No.5 in C minor, Op.67) represent perhaps the most well‐known and popular motif in classical music. The orchestral score is shown in the background of the cover graphic. Accessed March 20, 2013 from http://imslp.org/wiki/Symphony_No.5,_Op.67_%28Beethoven,_Ludwig_van%29 . 相似文献
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Yudong CaiBrian P Roberts 《Tetrahedron letters》2003,44(25):4645-4648
Terminal alkenes of the type H2CC(OR1)X, in which R1 is a tertiary alkyl or a 1-cyclopropylethyl group and X=Ph, OSiMe2But, OEt or H, undergo radical-chain reactions with organic halides R2Hal to give carbonyl compounds R2CH2C(O)X. 相似文献
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P. Bosch J. Serrano J. L. Mateo J. Guzmn P. Calle C. Sieiro 《Journal of polymer science. Part A, Polymer chemistry》1998,36(15):2785-2791
The reaction kinetics in the dark of photopolymerized mono- and dimethacrylates in a polymeric binder has been studied. Electron spin resonance spectroscopy (ESR) provided useful information regarding the nature of the radicals involved in postpolymerization reactions. Computer simulations were performed to study the decay of the propagating radicals by considering normal bimolecular termination and transfer reactions of the radicals to the binder. Differences were found in the termination reactions for mono- and difunctional monomers when they were photopolymerized in a solid medium. Absolute kinetic constants for H-transfer reaction with the binder, relative kinetic rate constants for radical–radical coupling, and average lifetimes for the radicals have been calculated. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2785–2791, 1998 相似文献
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H. Martin 《Angewandte Chemie (International ed. in English)》1966,5(1):78-84
Some recent examples of reactions proceeding both in the gas phase and in solution have been investigated to determine their kinetics and mechanisms. The ratio of the corresponding rate constants, kG and kL, of the elementary processes studied has been found to be about unity for unimolecular reactions and between 1 and 10 for bimolecular reactions. The mechanisms, overall rates, rate constants, and activation energies have been determined for the homogeneous gas reaction NOCl + Cl2O = NO2Cl + Cl2 and the reaction NOCl + N2O5 = NO2Cl + 2 NO2, carried out in C2F3Cl3. 相似文献
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Oxetane synthesis via cyclisation of aryl sulfonate esters on polystyrene and PEG polymeric supports
The addition of suitably protected pentaerythritols to polymer supported sulfonyl chloride with subsequent alkoxide formation and intramolecular cyclisation to generate oxetanes is described. This convenient method for the preparation of oxetanes has several advantages over analogous solution phase reactions and the methodology is extended to the preparation and use of a novel PEG-sulfonyl chloride. 相似文献
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Saleh Al-Mousawi Abdel-Zaher Elassar Morsy Ahmed El-Apasery 《Phosphorus, sulfur, and silicon and the related elements》2013,188(8):1755-1771
Heating diazoaminobenzene with active methylene compounds 1–3 in microwave oven in acetic acid, in the presence of hydrochloric acid, afforded the corresponding arylhydrazones 5–7. These reaction products were condensed with ethyl cyanoacetate in a domestic microwave oven after 1–2 minutes heating to yield the pyridazinones 8–12. Compounds 8c and 12 reacted with sulfur in basic DMF solution, in microwave oven using MORE technology to yield the thienopyridazinone 14 and 16 respectively. While 17 was produced when 8b was treated like wise with sulfur and DMF in the presence of piperidine. Compounds 16 coupled with aromatic diazonium salts to yield arylazo derivatives 21a–c. 相似文献
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Tomoaki Sugiyama Hiroya Shiba Dr. Masashi Yoshikawa Prof. Dr. Hiroaki Wada Prof. Dr. Atsushi Shimojima Prof. Dr. Kazuyuki Kuroda 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(11):2764-2772
The controlled synthesis of oligosiloxanes with well-defined structures is important for the bottom-up design of siloxane-based nanomaterials. This work reports the synthesis of various polycyclic and cage siloxanes by the hydrolysis and intramolecular condensation of monocyclic tetra- and hexasiloxanes functionalized with various alkoxysilyl groups. An investigation of monoalkoxysilylated cyclosiloxanes revealed that intramolecular condensation occurred preferentially between adjacent alkoxysilyl groups to form new tetrasiloxane rings. The study of dialkoxy- and trialkoxysilylated cyclotetrasiloxanes revealed multistep intramolecular condensation reactions to form cubic octasiloxanes in relatively high yields. Unlike conventional methods starting from organosilane monomers, intramolecular condensation enables the introduction of different organic substituents in controlled arrangements. So-called Janus cubes have been successfully obtained, that is, Ph4R4Si8O12, in which R=Me, OSiMe3, and OSiMe2Vi (Vi=vinyl). These findings will enable the creation of siloxane-based materials with diverse functions. 相似文献
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Simon J. Shaw 《合成通讯》2013,43(23):4183-4189
The treatment of benzocyclobutenol with a mild base has been investigated. This reaction results in an electrocyclic opening of the cyclobutene to the corresponding o‐quinodimethane, which has been successfully treated with aldehydes and electron‐deficient alkenes to form benzolactols and benzocyclohexenes respectively. 相似文献
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Jing Li Alexander Preinfalk Nuno Maulide 《Angewandte Chemie (International ed. in English)》2019,58(18):5887-5890
A flexible redox‐neutral coupling of aldehydes and alkenes enables rapid access to stereotriads starting from a single stereocenter with perfect levels of enantio‐ and diastereoselectivity under mild conditions. The versatility of the method is highlighted by the installation of heteroatoms along the tether, which enables a route to structurally diverse building blocks. The formal synthesis of (+)‐neopeltolide further demonstrates the synthetic utility of this approach. 相似文献