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21.
Timothy P. Moneypenny II Huiying Liu Anna Yang Ian D. Robertson Jeffrey S. Moore 《Journal of polymer science. Part A, Polymer chemistry》2017,55(18):2935-2948
Alkene metathesis has proven to be a powerful method for carbon carbon bond formation, particularly in the field of polymer and materials science. The availability of various tailor-made catalysts not only enables the synthesis of well-defined polymers but facilitates the development of functional, stimuli–responsive materials. This highlight, dedicated to Professor Robert Grubbs on his 75th birthday, focuses on the various research efforts in our group utilizing both alkene and alkyne metatheses and the interesting materials derived from them. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 2935–2948 相似文献
22.
Dr. Cédric Boulho Dr. Harmen S. Zijlstra Alexander Hofmann Prof. Dr. Peter H. M. Budzelaar Prof. Dr. Sjoerd Harder 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(48):17450-17459
Reaction of (TBBP)AlMe ? THF with [Cp*2Zr(Me)OH] gave [(TBBP)Al(THF)?O?Zr(Me)Cp*2] (TBBP=3,3’,5,5’‐tetra‐tBu‐2,2'‐biphenolato). Reaction of [DIPPnacnacAl(Me)?O?Zr(Me)Cp2] with [PhMe2NH]+[B(C6F5)4]? gave a cationic Al/Zr complex that could be structurally characterized as its THF adduct [(DIPPnacnac)Al(Me)?O?Zr(THF)Cp2]+[B(C6F5)4]? (DIPPnacnac=HC[(Me)C=N(2,6‐iPr2?C6H3)]2). The first complex polymerizes ethene in the presence of an alkylaluminum scavenger but in the absence of methylalumoxane (MAO). The adduct cation is inactive under these conditions. Theoretical calculations show very high energy barriers (ΔG=40–47 kcal mol?1) for ethene insertion with a bridged AlOZr catalyst. This is due to an unfavorable six‐membered‐ring transition state, in which the methyl group bridges the metal and ethene with an obtuse metal‐Me‐C angle that prevents synchronized bond‐breaking and making. A more‐likely pathway is dissociation of the Al‐O‐Zr complex into an aluminate and the active polymerization catalyst [Cp*2ZrMe]+. 相似文献
23.
Tadashi Kataoka Hironori Kinoshita 《Phosphorus, sulfur, and silicon and the related elements》2013,188(3-4):989-992
Abstract The Chalcogeno-Morita-Baylis-Hillman reaction was achieved by the reactions of 2-(methylchalcogeno)phenyl vinyl ketones with carbonyl compounds or acetals in the presence of BF3· Et2O. This reaction proceeds via the intramolecular Michael addition of the chalcogenide group to an enone moiety followed by the aldol reaction of the resulting chalcogenonio-enolate with an aldehyde. The reactions were worked up with triethylamine or saturated aqueous NaHCO3 to give the α -methylene aldols (the Morita-Baylis-Hillman adducts). 相似文献
24.
1,1‐Bis(4‐alkylthiophenyl)‐1‐alkenes were conveniently and efficiently prepared from alkyl phenyl sulfides and acyl chlorides via a tandem Friedel–Crafts acylation and alkylation in the presence of anhydrous aluminum chloride. The scope, limitation, and mechanism of the tandem reaction were also discussed. 相似文献
25.
The reaction of (hydroxymethyl)triphenylphosphonium with benzylic or allylic halide under basic conditions at room temperature affords terminal alkenes in 61–89% yields. In this reaction, both formaldehyde and triphenylphosphine are in situ generated from (hydroxymethyl)triphenylphosphonium and further undergo Wittig olefination with benzylic or allylic halide. 相似文献
26.
Nasser Iranpoor Elham Etemadi-Davan 《Phosphorus, sulfur, and silicon and the related elements》2014,189(7-8):1165-1173
27.
Sébastien Perdriau Mu‐Chieh Chang Dr. Edwin Otten Prof. Dr. Hero J. Heeres Prof. Dr. Johannes G. de Vries 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(47):15434-15442
The [Ru(CO)H(PNN)] pincer complex based on a dearomatised PNN ligand (PNN: 2‐di‐tert‐butylphosphinomethyl‐6‐diethylaminomethylpyridine) was examined for its ability to isomerise alkenes. The isomerisation reaction proceeded under mild conditions after activation of the complex with alcohols. Variable‐temperature (VT) NMR experiments to investigate the role of the alcohol in the mechanism lend credence to the hypothesis that the first step involves the formation of a rearomatised alkoxide complex. In this complex, the hemilabile diethylamino side‐arm can dissociate, allowing alkene binding cis to the hydride, enabling insertion of the alkene into the metal–hydride bond, whereas in the parent complex only trans binding is possible. During this study, a new uncommon Ru0 coordination complex was also characterised. The scope of the alkene isomerisation reaction was examined. 相似文献
28.
Sumin Lee Natthawat Semakul Tomislav Rovis 《Angewandte Chemie (International ed. in English)》2020,59(12):4965-4969
We report a RhIII‐catalyzed regio‐ and diastereoselective synthesis of δ‐lactams from readily available acrylamide derivatives and unactivated alkenes. The reaction provides a rapid route to a diverse set of δ‐lactams in good yield and stereoselectivity, which serve as useful building blocks for substituted piperidines. The regioselectivity of the reaction with unactivated terminal alkene is significantly improved by using Cpt ligand on the RhIII catalyst. The synthetic utility of the reaction is demonstrated by the preparation of a potential drug candidate containing a trisubstituted piperidine moiety. Mechanistic studies show that the reversibility of the C?H activation depends on the choice of Cp ligand on the RhIII catalyst. The irreversible C?H activation is observed and becomes turnover‐limiting with [CptRhCl2]2 as catalyst. 相似文献
29.
Xiaofeng Zhang Ting Cui Xin Zhao Ping Liu Peipei Sun 《Angewandte Chemie (International ed. in English)》2020,59(9):3465-3469
An electrochemical four‐component reaction cascade Mumm rearrangement was developed. It is a rare example of in situ generation of O‐acyl isoamides for 1,3‐(O→N) acyl transfer. Inexpensive, commercially available arylethylenes, aryl or heterocyclic acids, acetonitrile, and alcohols were used as substrates. A wide range of aryl acids and alcohols were tolerated and provided imides in satisfactory yields. Subsequent hydrolysis of imides could be utilized to synthesize valuable amides and β‐amino alcohol derivatives. 相似文献
30.
Fu‐Peng Wu Yang Yuan Claas Schünemann Paul C. J. Kamer Xiao‐Feng Wu 《Angewandte Chemie (International ed. in English)》2020,59(26):10451-10455
The borocarbonylative coupling of unactivated alkenes with alkyl halides remains a challenge. In this communication, a Cu‐catalyzed borocarbonylative coupling of unactivated alkenes with alkyl halides for the synthesis of β‐boryl ketones has been developed. A broad range of β‐boryl ketone derivatives was prepared in moderate to excellent yields with complete regioselectivity. 相似文献