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Activation of cyclopropanes by transition metals

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Structure of the platinacyclobutane PtC3H6(bipy) derived from activation of cyclopropane.

In organometallic chemistry, the activation of cyclopropanes by transition metals is a research theme with implications for organic synthesis and homogeneous catalysis.[1] Being highly strained, cyclopropanes are prone to oxidative addition to transition metal complexes. The resulting metallacycles are susceptible to a variety of reactions. These reactions are rare examples of C-C bond activation. The rarity of C-C activation processes has been attributed to Steric effects that protect C-C bonds. Furthermore, the directionality of C-C bonds as compared to C-H bonds makes orbital interaction with transition metals less favorable.[2] Thermodynamically, C-C bond activation is more favored than C-H bond activation as the strength of a typical C-C bond is around 90 kcal per mole while the strength of a typical unactivated C-H bond is around 104 kcal per mole.

Two main approaches achieve C-C bond activation using a transition metal. One strategy is to increase the ring strain and the other is to stabilize the resulting cleaved C-C bond complex (e.g. through aromatization or chelation). Because of the large ring strain energy of cyclopropanes (29.0 kcal per mole), they are often used as substrates for C-C activation through oxidative addition of a transition metal into one of the three C-C bonds leading to a metallacyclobutane intermediate.

Substituents on the cyclopropane affect the course of its activation.[3]

Reaction scope[edit]

Cyclopropane[edit]

The first example of cyclopropane being activated by a metal complex was reported in 1955, involving the reaction of cyclopropane and hexachloroplatinic acid. This reaction produces the polymeric platinacyclobutane complex Pt(C3H6)Cl2.[4][5] The bis(pyridine) adduct of this complex was characterized by X-ray crystallography.[6]

The electrophile Cp*Ir(PMe3)(Me)OTf reacts with cyclopropane to give the allyl complex:[7]

Cp*Ir(PMe3)(Me)OTf + C3H6 → [Cp*Ir(PMe3)(η3-C3H5)]OTf + CH4
Oxidative addition into cyclopropane C-C bond gives a metallacyclobutane.

Fused and spiro-cyclopropanes[edit]

Rhodium-catalyzed C-C bondactivation of strained spiropentanes leads to a cyclopentenones.[8] In terms of mechanism, the reaction proceeds by apparent oxidative addition of the 4-5 carbon-carbon bond, leading to a rhodacyclobutane intermediate. In the presence of carbon monoxide, migratory insertion of CO into one of the carbon-rhodium bonds gives a rhodacyclopentanone intermediate. Beta-carbon elimination to form an alkene from the other carbon-rhodium bond leads to a rhodacyclohexanone intermediate with an exocyclic double bond. Reductive elimination of the two carbon-rhodium bonds followed by isomerization of the exocyclic double bond leads to the desired beta-substituted cyclopentenone product. This reaction was applied to the total synthesis of (±)-β-cuparenone.

Using the same rhodium(I) catalyst and C-C bond activation strategy one can access compounds with fused rings.[9] Once again the reaction involves oxidative addition to give a rhodacyclobutane eventually affording a rhodacycloheptene intermediate. Insertion of carbon monoxide into one of the carbon-rhodium bonds form a rhodacyclooctenone intermediate that can reductively eliminate to yield a 6,7-fused ring system. The authors propose that the regioselectivity of the initial oxidative addition is controlled by coordination of the endocyclic double bond to the rhodium catalyst.

Cyclopropyl halides[edit]

Nickel(0) complexes oxidatively cleave halocyclopropanes to give allyl)Ni(II) halides.[10]

Cyclopropylketones[edit]

With cyclopropylketones, transition metal can coordinate to the ketone to direct oxidative addition into the proximal C-C bond. The resulting metallacyclobutane intermediate can be in equilibrium with the six-membered alkyl metal enolate depending on presence of a Lewis acid (e.g. dimethylaluminum chloride[11]).

With the metallacyclobutane intermediate, 1,2-migratory insertion into an alkyne followed by reductive elimination yields a substituted cyclopentene product. Examples of intramolecular reactions with a tethered alkyne[11] and intermolecular reactions with a nontethered alkyne[12] both exist with use of a nickel or rhodium catalyst. With the six-membered alkyl metal enolate intermediate, dimerization[13][14] or reaction with an added alpha-beta unsaturated ketone[15] yields a 1,3-substituted cyclopentane product.

Cyclopropylimines[edit]

Oxidative addition into cyclopropylimines gives a metalloenamine intermediate similar to oxidative addition to cyclopropylketones giving alkylmetalloenolates. These intermediates can also reaction with alpha-beta unsaturated ketones to give disubstituted cyclopentane products following reductive elimination.[16]

With rhodium, the intermediate metalloenamine reacts with tethered alkynes.[17] and alkenes[18] to give cyclized products such as pyrroles and cyclohexenones, respectively.

Alylidenecyclopropanes[edit]

Alkylidenecyclopropanes more readily undergo C-C bond oxidative addition than cyclopropanes.

Following oxidative addition, 1,2-insertion mechanisms are common and reductive elimination yields the desired product. The 1,2-insertion step usually occurs with an alkyne,[19] alkene,[20] or allene[21] and the final product is often a 5 or 7 membered ring. Six-membered rings may be formed after dimerization of the metallocyclobutane intermediate with another alkylidenecyclopropane substrate and subsequent reductive elimination.[22] Common transition metals utilized with alkylidenecyclopropanes are nickel, rhodium, and palladium. It has been shown that the metallacyclobutane intermediate following oxidative addition to the distal C-C bond can isomerize.[23]

Vinylcyclopropanes[edit]

Oxidative addition of vinylcyclopropanes primarily occurs at the proximal position, giving pi-allyl intermediates. Through subsequent insertion reactions (e.g. with alkynes,[24] alkenes,[25] and carbon monoxide[26]), rings of various sizes and fused ring systems[27] can be formed.

Cyclopropenes[edit]

Oxidative addition into cyclopropenes normally occurs at the less hindered position to yield the metallacyclobutane. This reaction can result in formation of cyclopentadienones,[28] cyclohexenones,[29] and phenols.[29]

References[edit]

  1. ^ Dong, Guangbin (2014). C-C Bond Activation. London: Springer. pp. 195–232. ISBN 978-3-642-55054-6.
  2. ^ Souillart, Laetitia; Cramer, Nicolai (2015-09-09). "Catalytic C–C Bond Activations via Oxidative Addition to Transition Metals". Chemical Reviews. 115 (17): 9410–9464. doi:10.1021/acs.chemrev.5b00138. ISSN 0009-2665. PMID 26044343.
  3. ^ Bart, Suzanne C.; Chirik, Paul J. (2003-01-01). "Selective, Catalytic Carbon−Carbon Bond Activation and Functionalization Promoted by Late Transition Metal Catalysts". Journal of the American Chemical Society. 125 (4): 886–887. doi:10.1021/ja028912j. ISSN 0002-7863. PMID 12537484.
  4. ^ Osdene, T. S.; Timmis, G. M.; Maguire, M. H.; Shaw, G.; Goldwhite, H.; Saunders, B. C.; Clark, Edward R.; Epstein, P. F.; Lamchen, M. (1955-01-01). "Notes". Journal of the Chemical Society (Resumed): 2038–2056. doi:10.1039/jr9550002038. ISSN 0368-1769.
  5. ^ Adams, D. M.; Chatt, J.; Guy, R. G.; Sheppard, N. (1961-01-01). "149. The Structure of "Cyclopropane Platinous Chloride"". Journal of the Chemical Society (Resumed). doi:10.1039/JR9610000738.
  6. ^ R.D. Gillard; M Keeton; R. Mason; M.F. Pilbrow; D.R. Russell (1971). "Cyclopropane Complexes of Platinum: Some Synthetic Studies and the Reactivity and Crystal Structure of 1,6-Dichloro-2,3-trimethylene-4,5-bis(pyridine)platinum(IV)". Journal of Organometallic Chemistry. 33 (2): 247–258. doi:10.1016/S0022-328X(00)88414-4.
  7. ^ Burger, Peter; Bergman, Robert G. (1993). "Facile intermolecular activation of carbon-hydrogen bonds in methane and other hydrocarbons and silicon-hydrogen bonds in silanes with the iridium(III) complex Cp*(PMe3)Ir(CH3)(OTf)". Journal of the American Chemical Society. 115 (22): 10462–3. doi:10.1021/ja00075a113.
  8. ^ Matsuda, Takanori; Tsuboi, Tomoya; Murakami, Masahiro (2007-10-01). "Rhodium-Catalyzed Carbonylation of Spiropentanes". Journal of the American Chemical Society. 129 (42): 12596–12597. doi:10.1021/ja0732779. ISSN 0002-7863. PMID 17914819.
  9. ^ Kim, Sun Young; Lee, Sang Ick; Choi, Soo Young; Chung, Young Keun (2008-06-16). "Rhodium-Catalyzed Carbonylative [3+3+1] Cycloaddition of Biscyclopropanes with a Vinyl Substituent To Form Seven-Membered Rings". Angewandte Chemie International Edition. 47 (26): 4914–4917. doi:10.1002/anie.200800432. ISSN 1521-3773. PMID 18496802.
  10. ^ Peganova, T. A.; Isaeva, L. S.; Petrovskii, P. V.; Kravtsov, D. N. (1990). "On the interaction of a nickel(0) complex with mono- and dibromo derivatives of cyclopropane. Novel η3-allylnickel complexes". Journal of Organometallic Chemistry. 384 (3): 397–403. doi:10.1016/0022-328X(90)87131-V.
  11. ^ a b Koga, Yuji; Narasaka, Koichi (1999-07-01). "Rhodium Catalyzed Transformation of 4-Pentynyl Cyclopropanes to Bicyclo[4.3.0]nonenones via Cleavage of Cyclopropane Ring". Chemistry Letters. 28 (7): 705–706. doi:10.1246/cl.1999.705. ISSN 0366-7022.
  12. ^ Tamaki, Takashi; Ohashi, Masato; Ogoshi, Sensuke (2011-12-09). "[3+2] Cycloaddition Reaction of Cyclopropyl Ketones with Alkynes Catalyzed by Nickel/Dimethylaluminum Chloride". Angewandte Chemie International Edition. 50 (50): 12067–12070. doi:10.1002/anie.201106174. ISSN 1521-3773. PMID 22006658.
  13. ^ Ogoshi, Sensuke; Nagata, Midue; Kurosawa, Hideo (2006-04-01). "Formation of Nickeladihydropyran by Oxidative Addition of Cyclopropyl Ketone. Key Intermediate in Nickel-Catalyzed Cycloaddition". Journal of the American Chemical Society. 128 (16): 5350–5351. doi:10.1021/ja060220y. ISSN 0002-7863. PMID 16620100.
  14. ^ Tamaki, Takashi; Nagata, Midue; Ohashi, Masato; Ogoshi, Sensuke (2009-10-05). "Synthesis and Reactivity of Six-Membered Oxa-Nickelacycles: A Ring-Opening Reaction of Cyclopropyl Ketones". Chemistry – A European Journal. 15 (39): 10083–10091. doi:10.1002/chem.200900929. ISSN 1521-3765. PMID 19718721.
  15. ^ Liu, Lei; Montgomery, John (2006-04-01). "Dimerization of Cyclopropyl Ketones and Crossed Reactions of Cyclopropyl Ketones with Enones as an Entry to Five-Membered Rings". Journal of the American Chemical Society. 128 (16): 5348–5349. doi:10.1021/ja0602187. ISSN 0002-7863. PMID 16620099.
  16. ^ Liu, Lei; Montgomery, John (2007-09-01). "[3+2] Cycloaddition Reactions of Cyclopropyl Imines with Enones". Organic Letters. 9 (20): 3885–3887. doi:10.1021/ol071376l. ISSN 1523-7060. PMID 17760449.
  17. ^ Chen, Gen-Qiang; Zhang, Xiao-Nan; Wei, Yin; Tang, Xiang-Ying; Shi, Min (2014-08-04). "Catalyst-Dependent Divergent Synthesis of Pyrroles from 3-Alkynyl Imine Derivatives: A Noncarbonylative and Carbonylative Approach". Angewandte Chemie International Edition. 53 (32): 8492–8497. doi:10.1002/anie.201405215. ISSN 1521-3773. PMID 24964965.
  18. ^ Shaw, Megan H.; McCreanor, Niall G.; Whittingham, William G.; Bower, John F. (2015-01-14). "Reversible C–C Bond Activation Enables Stereocontrol in Rh-Catalyzed Carbonylative Cycloadditions of Aminocyclopropanes". Journal of the American Chemical Society. 137 (1): 463–468. doi:10.1021/ja511335v. ISSN 0002-7863. PMID 25539136.
  19. ^ Delgado, Alejandro; Rodríguez, J. Ramón; Castedo, Luis; Mascareñas, José L. (2003-08-01). "Palladium-Catalyzed [3+2] Intramolecular Cycloaddition of Alk-5-ynylidenecyclopropanes: A Rapid, Practical Approach to Bicyclo[3.3.0]octenes". Journal of the American Chemical Society. 125 (31): 9282–9283. doi:10.1021/ja0356333. ISSN 0002-7863. PMID 12889943.
  20. ^ Gulías, Moisés; García, Rebeca; Delgado, Alejandro; Castedo, Luis; Mascareñas, José L. (2006-01-01). "Palladium-Catalyzed [3 + 2] Intramolecular Cycloaddition of Alk-5-enylidenecyclopropanes". Journal of the American Chemical Society. 128 (2): 384–385. doi:10.1021/ja054487t. ISSN 0002-7863. PMID 16402805.
  21. ^ Trillo, Beatriz; Gulías, Moisés; López, Fernando; Castedo, Luis; Mascareñas, José L. (2006-11-01). "Palladium-Catalyzed Intramolecular [3C+2C] Cycloaddition of Alkylidenecyclopropanes to Allenes". Advanced Synthesis & Catalysis. 348 (16–17): 2381–2384. doi:10.1002/adsc.200600347. ISSN 1615-4169.
  22. ^ Ohashi, Masato; Taniguchi, Tomoaki; Ogoshi, Sensuke (2010-06-14). "[3 + 3] Cyclodimerization of Methylenecyclopropanes: Stoichiometric and Catalytic Reactions of Nickel(0) with Electron-Deficient Alkylidenecyclopropanes". Organometallics. 29 (11): 2386–2389. doi:10.1021/om100317y. ISSN 0276-7333.
  23. ^ García-Fandiño, Rebeca; Gulías, Moisés; Castedo, Luis; Granja, Juan R.; Mascareñas, José L.; Cárdenas, Diego J. (2008-01-01). "Palladium-Catalysed [3+2] Cycloaddition of Alk-5-ynylidenecyclopropanes to Alkynes: A Mechanistic DFT Study". Chemistry – A European Journal. 14 (1): 272–281. doi:10.1002/chem.200700973. ISSN 1521-3765. PMID 17955506.
  24. ^ Shintani, Ryo; Nakatsu, Hiroki; Takatsu, Keishi; Hayashi, Tamio (2009-09-07). "Rhodium-Catalyzed Asymmetric [5+2] Cycloaddition of Alkyne–Vinylcyclopropanes". Chemistry – A European Journal. 15 (35): 8692–8694. doi:10.1002/chem.200901463. ISSN 1521-3765. PMID 19637169.
  25. ^ Wender, Paul A.; Haustedt, Lars O.; Lim, Jaehong; Love, Jennifer A.; Williams, Travis J.; Yoon, Joo-Yong (2006-05-01). "Asymmetric Catalysis of the [5 + 2] Cycloaddition Reaction of Vinylcyclopropanes and π-Systems". Journal of the American Chemical Society. 128 (19): 6302–6303. doi:10.1021/ja058590u. ISSN 0002-7863. PMID 16683779. S2CID 197039161.
  26. ^ Wang, Yuanyuan; Wang, Jingxin; Su, Jiachun; Huang, Feng; Jiao, Lei; Liang, Yong; Yang, Dazhi; Zhang, Shiwei; Wender, Paul A. (2007-08-01). "A Computationally Designed Rh(I)-Catalyzed Two-Component [5+2+1] Cycloaddition of Ene-vinylcyclopropanes and CO for the Synthesis of Cyclooctenones". Journal of the American Chemical Society. 129 (33): 10060–10061. doi:10.1021/ja072505w. ISSN 0002-7863. PMID 17655302.
  27. ^ Lin, Mu; Li, Feng; Jiao, Lei; Yu, Zhi-Xiang (2011-02-16). "Rh(I)-Catalyzed Formal [5 + 1]/[2 + 2 + 1] Cycloaddition of 1-Yne-vinylcyclopropanes and Two CO Units: One-Step Construction of Multifunctional Angular Tricyclic 5/5/6 Compounds". Journal of the American Chemical Society. 133 (6): 1690–1693. doi:10.1021/ja110039h. ISSN 0002-7863. PMID 21250688.
  28. ^ Wender, Paul A.; Paxton, Thomas J.; Williams, Travis J. (2006-11-01). "Cyclopentadienone Synthesis by Rhodium(I)-Catalyzed [3 + 2] Cycloaddition Reactions of Cyclopropenones and Alkynes". Journal of the American Chemical Society. 128 (46): 14814–14815. doi:10.1021/ja065868p. ISSN 0002-7863. PMID 17105285.
  29. ^ a b Li, Changkun; Zhang, Hang; Feng, Jiajie; Zhang, Yan; Wang, Jianbo (2010-07-02). "Rh(I)-Catalyzed Carbonylative Carbocyclization of Tethered Ene− and Yne−cyclopropenes". Organic Letters. 12 (13): 3082–3085. doi:10.1021/ol101091r. ISSN 1523-7060. PMID 20536190. S2CID 11710441.
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