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1.
Martin Petzold Peter G. Jones Daniel B. Werz 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(19):6291-6295
The first (3+3)‐annulation process of donor–acceptor cyclopropanes using synergistic catalysis is reported. The Rh2(OAc)4‐catalyzed decomposition of diazo carbonyl compounds generated carbonyl ylides in situ. These 1,3‐dipoles were converted with donor–acceptor cyclopropanes, activated by Lewis acid catalysis, to afford multiply substituted pyran scaffolds in high yield and diastereoselectivity. Extensive optimization studies enabled access to 9‐oxabicyclo[3.3.1]nonan‐2‐one and 10‐oxabicyclo[4.3.1]decen‐2‐ol cores, exploiting solvent effects on intermediate reactivity. 相似文献
2.
Donor‐acceptor cyclopropanes not only participate in a broad range of ring openings with nucleophiles, electrophiles, radical and red‐ox agents, but also are excellent substrates for various (3+n)‐cycloaddition and (3+n)‐annulation processes. Moreover, under treatment with Lewis acid donor‐acceptor cyclopropanes can produce new ring systems via isomerization or cyclodimerization. Authors’ contribution to the synthesis of diverse carbocycles from donor‐acceptor cyclopropanes is summarized in this account. 相似文献
3.
A New Type of Donor–Acceptor Cyclopropane Reactivity: The Generation of Formal 1,2‐ and 1,4‐Dipoles 下载免费PDF全文
Roman A. Novikov Anna V. Tarasova Victor A. Korolev Vladimir P. Timofeev Yury V. Tomilov 《Angewandte Chemie (International ed. in English)》2014,53(12):3187-3191
A new type of donor–acceptor cyclopropane reactivity has been discovered. On treatment with anhydrous GaCl3, they react as sources of even‐numbered 1,2‐ and 1,4‐dipoles instead of the classical odd‐numbered 1,3‐dipoles due to migration of positive charge from the benzyl center. This type of reactivity has been demonstrated for new reactions, namely, cyclodimerizations of donor–acceptor cyclopropanes that occur as [2+2]‐, [3+2]‐, [4+2]‐, [5+2]‐, [4+3]‐, and [5+4]‐annulations. The [4+2]‐annulation of 2‐arylcyclopropane‐1,1‐dicarboxylates to give polysubstituted 2‐aryltetralins has been developed in a preparative version that provides exceedingly high regio‐ and diastereoselectivity and high yields. The strategy for selective hetero‐combination of donor–acceptor cyclopropanes was also been developed. The mechanisms of the discovered reactions involving the formation of a comparatively stable 1,2‐ylide intermediate have been studied. 相似文献
4.
Denis D. Borisov Dr. Roman A. Novikov Prof. Dr. Yury V. Tomilov 《Angewandte Chemie (International ed. in English)》2016,55(40):12233-12237
A new strategy for cascade assembly of substituted indenes and polycyclic lactones based on reactions of donor–acceptor cyclopropanes and styrylmalonates with aromatic aldehydes in the presence of GaCl3 has been developed. The use of GaCl3 makes it possible to principally change the direction of the reaction known in this series of substrates and to perform the process in a multicomponent version. Generation of formal 1,2‐zwitterionic intermediates owing to complexation of dicarboxylate groups with GaCl3 is the driving force of the reactions discovered. This method makes it possible to assemble indenylmalonates or indano[1′,2′:2,3]indano[2,1‐b]furan‐2‐ones in one synthetic stage from readily available starting compounds with high regio‐ and diastereoselectivity. A mechanism of the reactions has been suggested using the 18O label in benzaldehyde. 相似文献
5.
Rh2(OAc)4‐Catalyzed decomposition of diazo esters in the presence of perfluoroalkyl‐ or perfluoroaryl‐substituted silyl enol ethers smoothly provided the corresponding alkyl 2‐siloxycyclopropanecarboxylates in very good yields. The generated donor? acceptor cyclopropanes are equivalents of γ‐oxo esters, which we demonstrated by their one‐pot transformations to yield fluorine‐containing heterocycles. A reductive procedure selectively afforded perfluoroalkyl‐substituted γ‐hydroxy esters or γ‐lactones. The treatment of the donor? acceptor cyclopropanes with hydrazine or phenylhydrazine afforded a series of perfluoroalkyl‐ and perfluoroaryl‐substituted 4,5‐dihydropyridazin‐3(2H)‐ones. 相似文献
6.
M. Sc. Lennart K. B. Garve Prof. Dr. Peter G. Jones Prof. Dr. Daniel B. Werz 《Angewandte Chemie (International ed. in English)》2017,56(31):9226-9230
The first ring-opening reaction of donor–acceptor cyclopropanes to give diamines is reported. For this reaction, a 1,3-bisfunctionalization was developed using cyclopropanes, triazinanes, and Sc(OTf)3 as the catalyst, followed by treatment with acid. The reaction proceeds under very mild conditions and tolerates many functional groups. Moreover, a library of various 1,3-diazepanes, which arise as intermediates of the first formal aza-[4+3]-cycloaddition reaction with donor–acceptor cyclopropanes, was synthesized. 相似文献
7.
Dr. Alexey O. Chagarovskiy Dr. Vladimir S. Vasin Dr. Vladimir V. Kuznetsov Dr. Olga A. Ivanova Dr. Victor B. Rybakov Dr. Alexey N. Shumsky Prof. Dr. Nina N. Makhova Prof. Dr. Igor V. Trushkov 《Angewandte Chemie (International ed. in English)》2018,57(32):10338-10342
The first example of (3+3)‐annulation of two different three‐membered rings is reported herein. Donor‐acceptor cyclopropanes in reaction with diaziridines were found to afford perhydropyridazine derivatives in high yields and diastereoselectivity under mild Lewis acid catalysis. The disclosed reaction is applicable for the broad substrate scope and exhibits an excellent functional group tolerance. 相似文献
8.
Dirhodium(II)‐Catalyzed Annulation of Enoldiazoacetamides with α‐Diazoketones: An Efficient and Highly Selective Approach to Fused and Bridged Ring Systems 下载免费PDF全文
Dr. Qing‐Qing Cheng Julietta Yedoyan Dr. Hadi Arman Prof. Dr. Michael P. Doyle 《Angewandte Chemie (International ed. in English)》2016,55(18):5573-5576
A dirhodium(II)‐catalyzed annulation reaction between two structurally different diazocarbonyl compounds furnishes the donor–acceptor cyclopropane‐fused benzoxa[3.2.1]octane scaffold with excellent chemo‐, regio‐, and diastereoselectivity under exceptionally mild conditions. The composite transformation occurs by [3+2]‐cycloaddition between donor–acceptor cyclopropenes generated from enoldiazoacetamides and carbonyl ylides formed from intramolecular carbene–carbonyl cyclization in one pot with one catalyst. The annulation products can be readily transformed into benzoxa[3.3.1]nonane and hexahydronaphthofuran derivatives with exact stereocontrol. This method allows the efficient construction of three fused and bridged ring systems, all of which are important skeletons of numerous biologically active natural products. 相似文献
9.
Ring Opening of Donor–Acceptor Cyclopropanes with the Azide Ion: A Tool for Construction of N‐Heterocycles 下载免费PDF全文
Konstantin L. Ivanov Dr. Elena V. Villemson Dr. Ekaterina M. Budynina Dr. Olga A. Ivanova Dr. Igor V. Trushkov Prof. Mikhail Ya. Melnikov 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(13):4975-4987
A general method for ring opening of various donor–acceptor cyclopropanes with the azide ion through an SN2‐like reaction has been developed. This highly regioselective and stereospecific process proceeds through nucleophilic attack on the more‐substituted C2 atom of a cyclopropane with complete inversion of configuration at this center. Results of DFT calculations support the SN2 mechanism and demonstrate good qualitative correlation between the relative experimental reactivity of cyclopropanes and the calculated energy barriers. The reaction provides a straightforward approach to a variety of polyfunctional azides in up to 91 % yield. The high synthetic utility of these azides and the possibilities of their involvement in diversity‐oriented synthesis were demonstrated by the developed multipath strategy of their transformations into five‐, six‐, and seven‐membered N‐heterocycles, as well as complex annulated compounds, including natural products and medicines such as (?)‐nicotine and atorvastatin. 相似文献
10.
Alexander Kreft Alexander Lücht Jrg Grunenberg Peter G. Jones Daniel B. Werz 《Angewandte Chemie (International ed. in English)》2019,58(7):1955-1959
The kinetics of (3+2) cycloaddition reactions of 18 different donor–acceptor cyclopropanes with the same aldehyde were studied by in situ NMR spectroscopy. Increasing the electron density of the donor residue accelerates the reaction by a factor of up to 50 compared to the standard system (donor group=phenyl), whereas electron‐withdrawing substituents slow down the reaction by a factor up to 660. This behavior is in agreement with the Hammett substituent parameter σ. The obtained rate constants from the (3+2) cycloadditions correlate well with data from additionally studied (3+n) cycloadditions with a nitrone (n=3) and an isobenzofuran (n=4). A comparison of the kinetic data with the bond lengths in the cyclopropane (obtained by X‐ray diffraction and computation), or the 1H and 13C NMR shifts, revealed no correlation. However, the computed relaxed force constants of donor–acceptor cyclopropanes proved to be a good indicator for the reactivity of the three‐membered ring. 相似文献
11.
In the presence of a catalytic amount of GaCl3, dimethyl 2‐(naphthalen‐1‐yl)cyclopropane‐1,1‐dicarboxylate 5 undergoes selective [3+2]‐annulation‐type dimerization to give a polysubstituted cyclopentane containing two naphthalenyl substituents in the vicinal position (Scheme 2). Treatment of the same cyclopropane with an equimolar amount of GaCl3?THF results in dimerization with electrophilic attack on each of the benzene rings to give [3+3] and [3+4] annulation products. The latter represent a new type of dimerization of donor? acceptor cyclopropanes. Finally, under conditions of double catalysis with GaCl3, 3,3,5,5‐tetrasubstituted 4,5‐dihydropyrazole, this cyclopropane‐dicarboxylate undergoes stereospecific dimerization as a result of electrophilic ipso‐attack to give a tetracyclic pentaleno[6a,1‐a]naphthalene derivative (Scheme 5). Possible reaction mechanisms are proposed. 相似文献
12.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(39):11993-11997
The first stereoselective organocatalyzed [3+2] cycloaddition reaction of donor‐acceptor cyclopropanes is presented. It is demonstrated that by applying an optically active bifunctional Brønsted base catalyst, racemic di‐cyano cyclopropylketones can be activated to undergo a stereoselective 1,3‐dipolar reaction with mono‐ and polysubstituted nitroolefins. The reaction affords functionalized cyclopentanes with three consecutive stereocenters in high yield and stereoselectivity. Based on the stereochemical outcome, a mechanism in which the organocatalyst activates both the donor‐acceptor cyclopropane and nitroolefin is proposed. Finally, chemoselective transformations of the cycloaddition products are demonstrated. 相似文献
13.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(38):11712-11716
Sn(OTf)2‐catalyzed 1,3‐aminobromination of donor–acceptor cyclopropanes with various sulfonyl amides or electron‐poor anilines and N ‐bromosuccinimide is reported. These experimentally straightforward reactions occurred with complete regio‐ and stereospecificity (for anilines) to give γ‐aminated α‐brominated malonic diesters in good to excellent yields (up to 98 %). These compounds served as valuable substrates for subsequent reactions to provide substituted azetidines and γ‐lactams in high yields. 相似文献
14.
Sophie Racine Florian de Nanteuil Eloisa Serrano Prof. Dr. Jérôme Waser 《Angewandte Chemie (International ed. in English)》2014,53(32):8484-8487
(Carbo)nucleoside derivatives constitute an important class of pharmaceuticals, yet there are only few convergent methods to access new analogues. Here, we report the first synthesis of thymine‐, uracil‐, and 5‐fluorouracil‐substituted diester donor–acceptor cyclopropanes and their use in the indium‐ and tin‐catalyzed [3+2] annulations with aldehydes, ketones, and enol ethers. The obtained diester products could be easily decarboxylated and reduced to the corresponding alcohols. The method gives access to a broad range of new (carbo)nucleoside analogues in only four or five steps and will be highly useful for the synthesis of libraries of bioactive compounds. 相似文献
15.
Yong Xia Lili Lin Fenzhen Chang Xuan Fu Xiaohua Liu Xiaoming Feng 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2015,127(46):13952-13956
A highly efficient asymmetric ring‐opening reaction of cyclopropyl ketones with a broad range of thiols, alcohols and carboxylic acids has been first realized by using a chiral N,N′‐dioxide–scandium(III) complex as catalyst. The corresponding sulfides, ethers, and esters were obtained in up to 99 % yield and 95 % ee. This is also the first example of one catalytic system working for the ring‐opening reaction of donor–acceptor cyclopropanes with three different nucleophiles, let alone in an asymmetric version. 相似文献
16.
Asymmetric Ring‐Opening of Cyclopropyl Ketones with Thiol,Alcohol, and Carboxylic Acid Nucleophiles Catalyzed by a Chiral N,N′‐Dioxide–Scandium(III) Complex 下载免费PDF全文
Yong Xia Dr. Lili Lin Fenzhen Chang Xuan Fu Prof. Dr. Xiaohua Liu Prof. Dr. Xiaoming Feng 《Angewandte Chemie (International ed. in English)》2015,54(46):13748-13752
A highly efficient asymmetric ring‐opening reaction of cyclopropyl ketones with a broad range of thiols, alcohols and carboxylic acids has been first realized by using a chiral N,N′‐dioxide–scandium(III) complex as catalyst. The corresponding sulfides, ethers, and esters were obtained in up to 99 % yield and 95 % ee. This is also the first example of one catalytic system working for the ring‐opening reaction of donor–acceptor cyclopropanes with three different nucleophiles, let alone in an asymmetric version. 相似文献
17.
Transition‐Metal‐Free Coupling Reaction of Vinylcyclopropanes with Aldehydes Catalyzed by Tin Hydride 下载免费PDF全文
Ryosuke Ieki Yuria Kani Dr. Shinji Tsunoi Prof. Ikuya Shibata 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(16):6295-6300
Donor–acceptor cyclopropanes are useful building blocks for catalytic cycloaddition reactions with a range of electrophiles to give various cyclic products. In contrast, relatively few methods are available for the synthesis of homoallylic alcohols through coupling of vinylcyclopropanes (VCPs) with aldehydes, even with transition‐metal catalysts. Here, we report that the hydrostannation of vinylcyclopropanes (VCPs) was effectively promoted by dibutyliodotin hydride (Bu2SnIH). The resultant allylic tin compounds reacted easily with aldehydes. Furthermore, the use of Bu2SnIH was effectively catalytic in the presence of hydrosilane as a hydride source, which established a coupling reaction of VCPs with aldehydes for the synthesis of homoallylic alcohols without the use of transition‐metal catalysts. In contrast to conventional catalytic reactions of VCPs, the presented method allowed the use of several VCPs in addition to conventional donor–acceptor cyclopropanes. 相似文献
18.
Enantioselective (4+2) Annulation of Donor–Acceptor Cyclobutanes by N‐Heterocyclic Carbene Catalysis 下载免费PDF全文
Alison Levens Adam Ametovski Prof. David W. Lupton 《Angewandte Chemie (International ed. in English)》2016,55(52):16136-16140
Herein we report the enantioselective (4+2) annulation of donor–acceptor cyclobutanes and unsaturated acyl fluorides using N‐heterocyclic carbene catalysis. The reaction allows a 3‐step synthesis of cyclohexyl β‐lactones (25 examples) in excellent chemical yield (most ≥90 %) and stereochemical integrity (all >20:1 d.r., most ≥97:3 e.r.). Mechanistic studies support ester enolate Claisen rearrangement, while derivatizations provide functionalized cyclohexenes and dihydroquinolinones. 相似文献
19.
Daniel B. Werz Akkattu T. Biju 《Angewandte Chemie (International ed. in English)》2020,59(9):3385-3398
Arynes and donor–acceptor (D–A) cyclopropanes are two classes of strained systems having the potential for numerous applications in organic synthesis. The last two decades have witnessed a renaissance of interest in the chemistry of these species primarily because of the mild and robust methods for their generation or activation. Commonly, arynes as easily polarizable systems result in 1,2‐disubstitution, whereas D‐A cyclopropanes as polarized systems lead to 1,3‐bisfunctionalization thereby showing striking similarities. Transformations with 1,2‐ and 1,3‐dipoles afford cyclic structures. With arynes, emerging four‐membered rings as intermediates might react further, whereas the analogous five‐membered rings obtained from D–A cyclopropanes are most often the final products. However, there are a few cases where these intermediates behave surprisingly differently. This Minireview highlights the parallels in reactivity between arynes and D–A cyclopropanes thereby shedding light on the neglected similarities of these two reactive species. 相似文献
20.
Asymmetric [3+2] Photocycloadditions of Cyclopropanes with Alkenes or Alkynes through Visible‐Light Excitation of Catalyst‐Bound Substrates 下载免费PDF全文
Xiaoqiang Huang Jiahui Lin Tianqi Shen Dr. Klaus Harms Dr. Marianna Marchini Prof. Dr. Paola Ceroni Prof. Dr. Eric Meggers 《Angewandte Chemie (International ed. in English)》2018,57(19):5454-5458
The herein reported visible‐light‐activated catalytic asymmetric [3+2] photocycloadditions between cyclopropanes and alkenes or alkynes provide access to chiral cyclopentanes and cyclopentenes, respectively, in 63–99 % yields and with excellent enantioselectivities of up to >99 % ee. The reactions are catalyzed by a single bis‐cyclometalated chiral‐at‐metal rhodium complex (2–8 mol %) which after coordination to the cyclopropane generates the visible‐light‐absorbing complex, lowers the reduction potential of the cyclopropane, and provides the asymmetric induction and overall stereocontrol. Enabled by a mild single‐electron‐transfer reduction of directly photoexcited catalyst/substrate complexes, the presented transformations expand the scope of catalytic asymmetric photocycloadditions to simple mono‐acceptor‐substituted cyclopropanes affording previously inaccessible chiral cyclopentane and cyclopentene derivatives. 相似文献