Lewis-Acid-Catalyzed Rearrangement of Arylvinylidenecyclopropanes:  Significant Influence of Substituents and Electronic Nature of Aryl Groups

Sydnes L.K.

Mizuno K., Maeda H., Sugita H., Nishioka S., Hirai T., Sugimoto A.

Photoirradiation of benzene solutions containing 1-diarylvinylidene-2,2,3,3-tetramethylcyclopropanes (2a−d) afforded rearranged products 1,2,3-butatrienes (3a−d) in good to high yields. Photorearrangement from 2,2,3-trimethyl and 2,2- and 2,3-dimethyl derivatives 2e−g also proceeded, but the rates of the rearrangement were lower than those of 2a−d. A singlet mechanism is proposed for this photorearrangement, where alkyl migration occurs from 1,3-biradical intermediates generated via the homolysis of the C1−C2 bond. Generation of diarylvinylidene carbenes from 1,3-biradicals might be competitive with the formation of 3.

Sugita H., Mizuno K., Saito T., Isagawa K., Otsuji Y.

The oxidation of (diphenylethenylidene) cyclopropanes and (dialkylethenylidene) cyclopropanes with m-chloroperbenzoic acid gave respectively 2-(diphenylethylidene) cyclobutan-1-ones and cyclopropyl keto esters with high selectivity. Graphic

Akasaka T., Misawa Y., Ando W.

Photosensitized oxygenation of adamantenylidenecyciopropanes ( 1 ) gave either the corresponding oxetanones ( 2a-c ) or the cyclic ketones ( 4 and 5 ) depending on the substituent on the cyclopropane ring in addition to adamantanone. The results are rationalized in terms of initial formation of a perepoxide followed by that of a peroxyallyl intermediate.

Smadja W.

Chevrier B., Weiss R.

Additionsverbindungen aus Lewis-Sauren MXn und Saurehalogeniden RCOX treten intermediar bei der Friedel-Crafts-Acylierung auf. IR- und NMR-Untersuchungen dieser Zwischenprodukte haben die Existenz von Strukturisomeren wahrscheinlich gemacht. Bei der Rontgen-Strukturanalyse lassen sich zwei Formen unterscheiden: die Molekulform, in der die Verbindungen als Donor-Acceptor-Komplexe RCXO←MXn vorliegen, und die Ionenform, in der sie als Oxocarbenium-Salze [RCO]+ [MXn—1]− formuliert werden konnen. Die Verbindungen vom Donor-Acceptor-Typ RCXO↔MXn zeichnen sich durch die Bildung einer koordinativen Sauerstoff-Metall-Bindung aus: der Elektronenubergang vom Sauerstoff zum Metall des Acceptors ruhrt immer von einer schwachen Donor-Acceptor-Wechselwirkung her. Die positive Ladung der Aryloxocarbenium-Ionen ist teilweise uber den aromatischen Kern delokalisiert. Im Gegensatz dazu befindet sich die positive Ladung bei den Alkyloxocarbenium-Ionen im wesentlichen auf dem Kohlenstoffatom der Carbonylgruppe, wie Berechnungen der Elektronendichteverteilung bestatigten.

Levinson A.S.

Poutsma M.L., Ibarbia P.A.

Bollinger J.M., Brinich J.M., Olah G.A.

Sergeev Pavel G., Novikov Roman G., Tomilov Yury V.

The strained structure of cyclopropanes serves as a kind of trigger for a variety of chemical transformations. Among others, processes involving conjugated unsaturated systems are of particular interest. The systems of unsaturated bonds are characterized by the possibility of flexibly varying their reactivity up to their full involvement in transformations. This review is the first to consider options for implementing the idea of combining the strain energy of cyclopropanes and the synthetic capacity of conjugated unsaturated systems within a single concept. A detailed analysis of processes involving activated cyclopropanes and numerous carbodiene and heterodiene systems is presented.The bibliography includes 289 references.

Chen M.

The development of Cu-catalyzed coupling of vinylidene cyclopropanes with allyl or allenyl boronates is reported.

Shao L., Lu J., Shi M.

Lewis or Brønsted acid-mediated intramolecular rearrangement of VDCPs, and the reactions of VDCPs with acetals, aldehydes, ketones, imines, activated alkenes, nitriles, acyl chlorides, and alcohols are described in this chapter.

Yuan W., Wei Y., Shi M., Li Y.

Lu B., Dai L., Shi M.

Gold-catalyzed reactions, which have been widely explored over the past several years, are powerful tools in organic synthesis to access complex molecular frameworks, and some corresponding excellent reviews have been reported. However, little attention has been paid to summarize the reactions of strained small-ring-containing molecules catalyzed by gold. This critical review mainly puts its emphasis on the recent progress in the field of gold-catalyzed transformations of cyclopropyl-, cyclopropenyl-, epoxy- and aziridinyl-containing molecules. The rapid construction of interesting building blocks in organic synthesis from strained small rings catalyzed by gold has been summarized in this review (106 references).

Lu B., Lu J., Shi M.

LDA-mediated cascade carbolithiation reactions of vinylidenecyclopropanes with enones and N-sulfonated imines as well as nitroalkene and (phenylmethylidene)malononitrile in THF at –78 °C have been realized; the corresponding novel adducts were produced in moderate to good yields with moderate to high diastereoselectivities. The scope and limitations are discussed as well as a plausible reaction mechanism based on control experiments performed in this work and previous literature reports.

Larina A.G., Stepakov A.V., Boitsov V.M., Molchanov A.P., Gurzhiy V.V., Starova G.L., Lykholay A.N.

The first example of 1,3-dipolar cycloaddition reactions of nitrones to vinylidenecyclopropanes is described. The nitrones react with the C1′–C2′ double bond of vinylidenecyclopropanes to give the corresponding 4-cyclopropylidene-isoxazolidines in moderate yields.

Wu L., Shi M.

Yuan W., Wei Y., Shi M.

Manganese(III)-mediated oxidative annulation of vinylidenecyclopropanes with 1,3-dicarbonyl compounds in acetonitrile/acetic acid produces the corresponding functionalized dihydrofuran derivatives in moderate to good yields under mild conditions. The substrate scope has been examined and a plausible reaction mechanism has been also proposed on the basis of experimental results and previous literature. (C) 2011 Elsevier Ltd. All rights reserved.

Yu L., Guo R.

Introduction .......................................................................................210 I. Preparation of MCPs..........................................................................210 1. MCPs without Additional Functional Groups.............................................. 210 2. MCPs with Functional Groups on the C C Bond ....................................... 211 3. MCPs with Functional Groups on the Cyclopropyl Ring .............................. 212 4. Vinylidenecyclopropanes and Alkylidenecyclopropa[b]naphthalenes ............ 212 5. Recently Developed Methods for the Synthesis of MCPs .............................. 213 II. Transition Metal-catalyzed Reactions of MCPs...................................217 1. Palladium-catalyzed Reactions of MCPs ..................................................... 219 2. Nickelor Platinum-catalyzed Reactions of MCPs ....................................... 225 3. Coinage Metal-catalyzed Reactions of MCPs............................................... 228 4. Other Transition Metal-catalyzed Reactions of MCPs .................................. 232 III. Free Radical Reactions of MCPs.........................................................233 1. Reactions With Carbon Free Radicals......................................................... 234 2. Reactions With Phosphorus, Sulfur or Selenium Free Radicals.................... 234 3. Other Examples of MCP Free Radical Reactions......................................... 240 IV. Direct Additions of Electrophiles to MCPs..........................................240 1. Addition of Protons.................................................................................... 240 2. Addition of Halogen Cations ...................................................................... 240 3. Addition of Sulfur or Selenium Cations ...................................................... 242 V. Lewis Acid Catalyzed Reactions of MCPs...........................................243 1. Addition of Protic Nucleophiles .................................................................. 243 2. Cycloadditions........................................................................................... 244 3. Friedel-Crafts Reactions ............................................................................ 245 4. Additions of Acyl Chloride ......................................................................... 248 5. Se Se or S S Bond Cleavage and the Electrophilic Addition to MCPs........ 250 6. Rearrangements ........................................................................................ 251 7. Other Reactions......................................................................................... 251 VI. Other Types of Reactions....................................................................253 Conclusion .........................................................................................253 Acknowledgement ..............................................................................254 References..........................................................................................254

Wu L., Shi M.

Ring-opening reaction of vinylidenecyclopropanediesters catalyzed by Re2(CO)10 or Yb(OTf)3 afforded 2H-pyran-2-one derivatives or α,β-unsaturated ketones in moderate to good yields through a highly regioselective carbon–carbon bond cleavage pathway. The substituents at the cyclopropane mainly determine the regioselectivity of the carbon–carbon bond cleavage, providing different products of tandem ring-opening and rearrangement reactions.

Su C., Cao J., Huang X., Wu L., Huang X.

Lu B., Shi M.

Pellissier H.

This review is intended to update the recent developments in the reactivity of methylene- and alkylidenecyclopropanes, covering the literature from 2003 to 2010. The highly strained structure of these atypical compounds allows an otherwise unattainable chemical reactivity in many diverse synthetic applications, such as ring-opening reactions, cycloaddition reactions, rearrangements, radical reactions, polymerisation reactions and miscellaneous reactions including addition reactions with ring conservation and Heck reactions.

Lu B., Wei Y., Shi M.