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951.
Fabien Rodier Michel Rajzmann Dr. Jean‐Luc Parrain Dr. Gaëlle Chouraqui Dr. Laurent Commeiras 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(7):2467-2477
The synthetic utility of γ‐alkylidenebutenolides is demonstrated as highly competent dipolarophile partners in both intra‐ and intermolecular rhodium(II)‐catalyzed 1,3‐dipolar cycloaddition reactions. The strength of this approach lies in the formation of spiro[6,4]lactone moieties with the concomitant construction of quaternary spiro stereocenters. Typically, the construction of spirolactones involves an esterification step, which has often been reported as a “biosynthetic pathway”, and often occurs either as or near to the final step of a total synthesis. Furthermore, a convergent and versatile route is reported for the formation of the (5,7) skeleton of molecules that were isolated from the Schisandra genus. Computational studies were performed to provide an overall picture of the mechanism of the intermolecular [3+2] cycloaddition between 2‐diazo‐1,3‐ketoester and protoanemonin and to rationalize the empirical observations. In particular, we have demonstrated for the first time that the rhodium center plays an important role during the cyclization step itself and reacts with the dipolarophile as a complex with the ylide. 相似文献
952.
Yanxia Zhao Dr. Yibo Lei Qingsong Dong Prof. Biao Wu Prof. Xiao‐Juan Yang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(36):12059-12066
The reactions of dialumane [L(thf)Al? Al(thf)L] ( 1 , L=[{(2,6‐iPr2C6H3)NC(Me)}2]2?) with stilbene and styrene afforded the oxidation/insertion products [L(thf)Al(CH(Ph)? CH(Ph))AlL] ( 2 ) and [L(thf)Al(CH(Ph)? CH2)Al(thf)L] ( 3 ), respectively. In the presence of Na metal, precursor 1 reacted with butadienes, possibly through the reduced “dialumene” or the “carbene‐like” :AlL species, to yield aluminacyclopentenes [LAl(CH2C(Me)?C(Me)CH2)Na]n ( 4 a ) and [Na(dme)3][LAl(CH2C(Me)?CHCH2)] ( 4 b , dme=dimethoxyethane) as [1+4] cycloaddition products, as well as the [2+4] cycloaddition product 1,6‐dialumina‐3,8‐cyclodecadiene, [{Na(dme)}2][LAl(CH2C(Me)?C(Me)CH2)2AlL] ( 5 ). The possible mechanisms of the cycloaddition reactions were studied by using DFT computations. 相似文献
953.
954.
Ozgul Gok Sezin Yigit Meliha Merve Kose Rana Sanyal Amitav Sanyal 《Journal of polymer science. Part A, Polymer chemistry》2013,51(15):3191-3201
Diblock and triblock dendron–polymer conjugates containing biodegradable polyester dendron blocks and polyethylene glycol (PEG) polymer were synthesized using the Diels–Alder “click” cycloaddition reaction. PEG polymers with furan‐protected maleimide functionality were synthesized and reacted with biodegradable polyester dendrons containing an anthracene moiety at their focal point. First through third generations of biodegradable polyester dendrons containing an anthracene unit at their focal point were synthesized using a divergent strategy. Efficient conjugation of the dendrons to polymers was demonstrated using 1HNMR and size exclusion chromatography. This modular approach provides an easy access to the design of multivalent PEG conjugates. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 3191–3201 相似文献
955.
New nonlinear compounds containing 1,4‐diaryl‐[1,2,3]‐triazole were prepared using a straightforward and efficient method for the regioselective synthesis of [1,2,3]‐triazoles. The methodology consists of a Cu(I)‐catalyzed 1,3‐dipolar cycloaddition of aryl azides to terminal arylacetylenes (click reaction). All compounds exhibited liquid‐crystalline profile. 相似文献
956.
A new cascade reaction including formal [5?+?2] cycloaddition was developed. Treatment of homocinnamyl alcohol and Co2(CO)6-complexed arylpropynal with BF3·OEt2 resulted in the generation of hydrobenzocycloheptafuran having an alkyne-Co2(CO)6 complex. The reaction consists of 5-membered ring selective Prins cyclization and subsequent Friedel-Crafts cyclization. The cascade reaction was applied to a further multi-step cascade cyclization, which resulted in the formation of more complex polycyclic hydrofurans. 相似文献
957.
Y. A. Al-Soud I. A. Al-Masoudi B. Saeed U. Beifuß N. A. Al-Masoudi 《Chemistry of Heterocyclic Compounds》2006,42(5):583-590
A variety of 7-[(1,5-dialkyl-1H-1,2,4-triazolyl)methoxy(and methyl)]coumarins were synthesized from cycloaddition of 2-(2H-benzopyran-7-yloxy)acetonitrile
and 2-(5-methoxy-4-methyl-2H-benzopyran-7-yloxy)acetonitrile, respectively, with various reactive cumulene
intermediates via spontaneous rearrangements. The anticancer (breast, lung, CNS cancers) and antiviral (HIV-1, HIV-2) properties
of some compounds were investigated in vitro. 5-Methoxy-4-methyl-7-[(6,7,8,9-tetrahydro-5H-[1,2,4]triazolo[1,5-a]azepin-2-yl)methyl]coumarin
showed some inhibition of HIV-1.
Published in Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 669–678, May, 2006. 相似文献
958.
T. Sasamori E. Mieda N. Nagahora N. Tokitoh 《Chemistry of Heterocyclic Compounds》2006,42(12):1603-1609
The synthesis of a 1-oxa-5-aza-2,3-distibacyclopent-4-ene derivative by the [2+3]cycloaddition reaction of a kinetically stabilized
distibene, BbtSb=SbBbt (Bbt = 2,6-bis[bis(trimethylsilyl)methyl]-4-[tris-(trimethylsilyl)methyl]phenyl), with MesCNO (Mes
= mesityl) has been performed.
Dedicated to Prof. Dr. E. Lukevics on the occasion of his 70th birthday
__________
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1880–1887, December, 2006. 相似文献
959.
Dr. Takayuki Iwata Mizuki Hyodo Takuto Fukami Prof. Dr. Yoshihito Shiota Prof. Dr. Kazunari Yoshizawa Prof. Dr. Mitsuru Shindo 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(39):8506-8510
We report herein an efficient method to synthesize triptycenes by the reaction of benzynes and anthranoxides, which are electron-rich and readily prepared from the corresponding anthrones. Using this method, 1,9-syn-substituted triptycenes were regioselectively obtained employing 3-methoxybenzynes. This method was also applied to synthesize pentiptycenes. A DFT study revealed that the cycloaddition of lithium anthranoxide and benzyne proceeds stepwise. 相似文献
960.
Pau Besalú-Sala Dr. Josep M. Luis Prof. Dr. Miquel Solà 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(63):14481-14487
In the last 30 years, fullerene-based materials have become popular building blocks for devices with a broad range of applications. Among fullerene derivatives, endohedral metallofullerenes (EMFs, M@Cx) have been widely studied owing to their unique properties and reactivity. For real applications, fullerenes and EMFs must be exohedrally functionalized. It has been shown that encapsulated metal cations facilitate the Diels–Alder reaction in fullerenes. Herein, the Bingel–Hirsch (BH) addition of ethyl bromomalonate over a series of ion-encapsulated M@C60 (M=Ø, Li+, Na+, K+, Mg2+, Ca2+, and Cl−; Ø@C60 stands for C60 without any endohedral metal) is quantum mechanically explored to analyze the effect of these ions on the BH addition. The results show that the incarcerated ion has a very important effect on the kinetics and thermodynamics of this reaction. Among the systems studied, K+@C60 is the one that leads to the fastest BH reaction, whereas the slowest reaction is given by Cl−@C60. 相似文献