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101.
Synthesis of conformationally restricted dispiro- and bis-dispiro-1,3-dioxolanes via three-component reaction of diazoamides, ketoamides/diketones, and aromatic/heteroaromatic aldehydes in the presence of rhodium(II) acetate dimer catalyst at room temperature involving carbonyl ylides is demonstrated with diastereoselectivity. Synthesis of macrocyclic dispiro-1,3-dioxolanes via intramolecular carbonyl ylide is also delineated in high yield. The conformationally restricted symmetrical as well as unsymmetrical dispiro-1,3-dioxolanes were obtained under mild conditions in a highly diastereo- and regioselective manner. 相似文献
102.
A simple, convenient and efficient protocol for the construction of an array of glycospiro-pyrroloisoquinolines using isoquinolinium ylide and a carbohydrate-derived exocyclic olefin in the presence of Cu(OTf)2–Et3N catalytic system is described. Isoquinoline and alkylbromoacetates/2-bromoacetophenones were employed to generate the azomethine ylides in the presence of Et3N in refluxing toluene and subsequent exposure to the olefin led to the desired isoquinoline derivatives. 相似文献
103.
Disclosed herein is an efficient Ag-catalyzed 4+1 heteroannulation reaction of enamides with α-carbonyl sulfoxonium ylides.The diastereoselective transformation provides a practical access to a diverse range of multi-functionalized oxazoline derivatives.The synthetic utility of the resultant tetrasubstituted oxazolines is further demonstrated by a series of useful manipulations into valuable building blocks of pharmaceutical relevance. 相似文献
104.
Hematite(α-Fe_2O_3) is a promising photoanode for photoelectrochemical(PEC) water splitting.However,the severe charge recombination and sluggish water oxidation kinetics extremely limit its use in photohydrogen conversion.Herein,a co-activation strategy is proposed,namely through phosphorus(P)doping and the loading of CoAl-layered double hydroxides(CoAl-LDHs) cocatalysts.Unexpectedly,the integrated system,CoAl-LDHs/P-Fe_2O_3 photoanode,exhibits an outstanding photocurrent density of 1.56 mA/cm~2 at 1.23 V(vs.reversible hydrogen electrode,RHE),under AM 1.5 G,which is 2.6 times of pureα-Fe_2O_3.Systematic studies reveal that the remarkable PEC performance is attributed to accelerated surface OER kinetics and enhanced carrier separation efficiency.This work provides a feasible strategy to enhance the PEC performance of hematite photoanodes. 相似文献
105.
Diana V. Aleksanyan Yulia V. Nelyubina Zinaida S. Klemenkova Vladimir A. Kozlov 《Phosphorus, sulfur, and silicon and the related elements》2014,189(7-8):1028-1042
AbstractNovel phosphorus-containing ligands have been synthesized by the condensation of 2-(thio)phosphorylated anilines with 2,6-dichloro- and 4-chloropyridine-2-carbonyl chlorides in the presence of Et3N and unsubstituted pyridine-2-carboxylic acid using P(OPh)3 as a coupling agent. The compounds derived readily form complexes with a range of transition metals (M=Re(I), Pd(II), and Cu(II)), serving as bi- or tridentate monoanionic ligands. The composition and structure of the resulting metallocycles depend both on the presence/amount of the Cl atoms in the pyridine ring and on the nature of the donor atom X in the P=X moiety. The novel compounds were characterized by multinuclear NMR and IR spectroscopy as well as X-ray crystallography. 相似文献
106.
Weijie Chen Dr. YoungKu Kang Dr. Richard G. Wilde Prof. Dr. Daniel Seidel 《Angewandte Chemie (International ed. in English)》2014,53(20):5179-5182
In contrast to the continuously growing number of methods that allow for the efficient α‐functionalization of amines, few strategies exist that enable the direct functionalization of amines in the β‐position. A general redox‐neutral strategy is outlined for amine β‐functionalization and α,β‐difunctionalization that utilizes enamines generated in situ. This concept is demonstrated in the context of preparing polycyclic N,O‐acetals from simple 1‐(aminomethyl)‐β‐naphthols and 2‐(aminomethyl)‐phenols. 相似文献
107.
108.
Joachim W. Heinicke Nidhi Gupta Peter Mayer Konstantin Karaghiosoff 《无机化学与普通化学杂志》2020,646(13):959-963
NH-Functional 1H-1,3-benzazaphospholes 1a–1c and o-chloranil (tetrachloro-o-benzoquinone - TCBQ) undergo rapid [1+4]-cycloaddition in a 1:2 molar ratio to give 2a – 2c as high-melting zwitterionic σ6λ5-phosphorus compounds. In the case of 2a the yield is high (rel. to TCBQ) even if the reactants were used in a 1:0.5 molar ratio. For the 2-tert-butyl-substituted compounds 2b and 2c the yields were significantly lower, in part by unidentified byproducts. Addition of excess TCBQ to crude 2c containing unconverted 1c did not increase but strongly decrease the amount of 2c . Crystallization and XRD analysis led to detection of a minor side or consecutive product 3c , formally corresponding to P=C bond cleavage and [1+4] cycloaddition of three equivalents TCBQ, two at the phosphinidene and one at the carbene end. NMR spectroscopic data of 2a – 2c including conclusive 13C data for 2a give evidence of the structures of the new compounds. 相似文献
109.
Christian Knittl-Frank Iakovos Saridakis Thomas Stephens Dr. Rafael Gomes Dr. James Neuhaus Dr. Antonio Misale Dr. Rik Oost Dr. Alberto Oppedisano Prof. Dr. Nuno Maulide 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(48):10972-10975
The metal-promoted nucleophilic addition of sulfur ylides to π-systems is a well-established reactivity. However, the driving force of such transformations, elimination of a sulfide moiety, entails stoichiometric byproducts making them unfavorable in terms of atom economy. In this work, a new take on sulfur ylide chemistry is reported, an atom-economical gold(I)-catalyzed synthesis of dihydrobenzo[b]thiepines. The reaction proceeds under mild conditions at room temperature. 相似文献
110.
ICP-AES测定镍基焊料中的磷 总被引:1,自引:0,他引:1
通过酸溶解试验、基体共存元素干扰实验等,建立了ICP-AES测定镍基焊料中高含量磷的分析方法.样品加标回收率为100.5%-101.0%,相对标准偏差小于0.80%.该方法简便、快速、准确可靠. 相似文献