Synlett 2018; 29(06): 717-722
DOI: 10.1055/s-0037-1609339
cluster
© Georg Thieme Verlag Stuttgart · New York

Ruthenium- and Rhodium-Catalyzed Ring-Opening Coupling Reactions of Cyclopropenones with Alkenes or Alkynes

Teruyuki Kondo*
a   Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan   Email: teruyuki@scl.kyoto-u.ac.jp
,
Ryosuke Taniguchi
a   Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan   Email: teruyuki@scl.kyoto-u.ac.jp
,
Yu Kimura
b   Research and Educational Unit of Leaders for Integrated Medical Systems, Center for the Promotion of Interdisciplinary Education and Research, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan
› Author Affiliations
Further Information

Publication History

Received: 20 January 2018

Accepted after revision: 18 February 2018

Publication Date:
01 March 2018 (online)


Published as part of the Cluster C–C Activation

Abstract

Ru3(CO)12-catalyzed divergent ring-opening coupling reactions of a cyclopropenone with methyl acrylate (an electron-deficient alkene) are developed. Under an argon atmosphere, a decarbonylative linear codimer is obtained, while cyclopentenones are obtained under carbon monoxide (20 atm) without decarbonylation. While ruthenium complexes show no catalytic activity for the ring-opening cocyclization of cyclopropenones with ethylene (20 atm) or bicyclo[2.2.1]hept-2-ene (2-norbornene), rhodium complexes, especially [RhCl(η4-1,5-cod)]2, show high catalytic activity for the desired cocyclization reactions to give the corresponding cyclopentenones in high yields and selectivities. In addition, [RhCl(η4-1,5-cod)]2 realizes the catalytic ring-opening co­cyclization of cyclopropenones with internal alkynes to give the corresponding cyclopentadienones. In all these reactions, ruthena- or rhodacyclobutenones are considered to be key intermediates, generated by strain-driven oxidative addition of a cyclopropenone C–C bond to an ­active ruthenium or rhodium species.

Supporting Information

 
  • References and Notes

  • 6 Ko HM. Dong G. Nat. Chem. 2014; 739
  • 8 For the first catalytic cleavage of a C–C bond in unstrained tert-homoallylic alcohols through β-carbon elimination, see: Kondo T. Kodoi K. Nishinaga E. Okada T. Morisaki Y. Watanabe Y. Mitsudo T. J. Am. Chem. Soc. 1998; 120: 5587
  • 12 Although the Ni(0)-catalyzed ring-opening dimerization of cyclopropenones to give 1,4-benzoquinones has been developed, no catalytic ring-opening coupling reactions of cyclopropenones with alkenes have been reported so far. See: Noyori R. Umeda I. Takaya H. Chem. Lett. 1972; 1189 . As for Rh(I) catalyzed ring-opening coupling reaction of cyclopropenones with alkynes, see Ref. 16
  • 13 The reactions using other cyclopropenones such as 2,3-dipropylcycloprop-2-en-1-one and bicyclo[6.1.0]non-1(8)-en-9-one competed with decarbonylation of cyclopropenones, and the corresponding alkynes were formed as the main products. Accordingly, a careful tuning of the reaction conditions for each cyclopropenone is apparently required. As shown in Scheme 1, compounds 3 and 4 were obtained in moderate yields due to the decarbonylation of 1 to give 1,2-diphenylethyne. However, no other by-products which disturb analysis and isolation of the desired compounds 3 and 4 were obtained at all.
    • 14a Wong W. Singer SJ. Pitts WD. Watkins SF. Baddley WH. J. Chem. Soc., Chem. Commun. 1972; 672
    • 14b Foerstner J. Kakoschke A. Wartchow R. Butenschön H. Oragnometallics 2000; 19: 2108
  • 15 The free energy profiles of ruthenacycles such as ruthenacyclobutenone, ruthenacyclopentene, and (maleoyl)ruthenium complexes as well as the orbital interactions in the insertion of ethylene or bicyclo[2.2.1]hept-2-ene were calculated by the BP86 density functional theory (DFT) method, see Ref. 19. The 6-31G* basis set was used for C, H, and O atoms, and Stuttgart/Dresden’s pseudopotential SDD basis set (see Ref. 20) was used for the Ru atom. See: Wang C., Wu Y.-D.; Organometallics; 2008, 27: 6152
  • 16 Wender and co-workers also reported a similar [RhCl(CO)]2-catalyzed ring-opening cocyclization of cyclopropenones with alkynes to give cyclopentadienones; however, the reaction of 1 with 11h gave 12h selectively without 12h′, see: Wender PA. Paxton TJ. Williams TJ. J. Am. Chem. Soc. 2006; 128: 14814
  • 17 Nishinaga A. Nakamura K. Matsuura T. J. Org. Chem. 1982; 47: 1431
  • 18 Ruthenium-Catalyzed Divergent Ring-Opening Coupling Reactions of 2,3-Diphenylcycloprop-2-en-1-one (1) with Methyl Acrylate (2); General ProcedureA mixture of 2,3-diphenylcycloprop-2-en-1-one (1) (1.0 mmol), methyl acrylate (2) (3.0 mL), and Ru3(CO)12 (0.066 mmol) was placed in a two-necked 20-mL Pyrex flask equipped with a magnetic stir bar and a reflux condenser under a flow of argon. The reactor was connected to a balloon (1 L) and the reaction was carried out at 100 °C for 20 hours with stirring. After the reaction mixture had been cooled, the products were analyzed by GC and GC/MS, and isolated by medium-pressure column chromatography (SiO2 60 μm, eluent: EtOAc/hexane). The reactions under carbon monoxide pressure were carried out in a 50-mL stainless steel autoclave at 160 °C for 20 hours.Rhodium-Catalyzed Ring-Opening Cocyclization of 2,3-Diphenylcycloprop-2-en-1-one (1) with Alkenes/Alkynes; General ProcedureA mixture of 2,3-diphenylcycloprop-2-en-1-one (1) (1.0–1.5 mmol), [RhCl(η4-1,5-cod)]2 (0.10 mmol), solvent (3.0 mL), and an alkene (3.0 mmol) or an alkyne (1.0 mmol) was placed in a two-necked 20-mL Pyrex flask equipped with a magnetic stir bar and a reflux condenser under a flow of argon. The reactor was connected to a balloon (1 L) and the reaction was carried out at 100 °C for 20 hours with stirring. After the reaction mixture had been cooled, the products were analyzed by GC and GC/MS, and isolated by medium-pressure column chromatography (SiO2 60 μm, eluent: EtOAc/hexane). The reactions under ethylene were carried out in a 50-mL stainless steel autoclave.The MS and NMR data of the representative new compounds, 4, 8, 12h, and 12h′ are reported below. See also the Supporting Information.Methyl 4-Oxo-2,3-diphenylcyclopent-2-ene-1-carboxylate (4)Yield: 137.2 mg (47%); pale yellow solid; 1H NMR (300 MHz, CDCl3): δ = 2.75–2.93 (dd, J = 16.0, 18.5 Hz 1 H), 2.76–2.95 (dd, J = 20.0, 18.5 Hz, 1 H), 3.50 (s, 3 H), 4.25–4.28 (dd, J = 4.2, 3.0 Hz, 1 H), 7.11–7.25 (m, 10 H); 13C NMR (75 MHz, CDCl3): δ = 39.26, 46.76, 52.42, 128.18, 128.23, 128.35, 128.45, 129.45, 129.87, 131.13, 133.99, 141.07, 164.94, 172.62, 204.60; MS (EI): m/z = 292 (M+). exo-2,3-Diphenyl-3a,4,5,6,7,7a-hexahydro-1H-4,7-methanoinden-1-one (8)Yield: 183.0 mg (61%); orange solid; 1H NMR (300 MHz, CDCl3): δ = 0.98–1.04 (m, 1 H), 1.21–1.27 (m, 1 H), 1.38–1.44 (m, 2 H), 1.62–1.68 (m, 2 H), 2.10–2.36 (m, 1 H), 2.50 (d, J = 5.4 Hz, 1 H), 2.59–2.62 (m, 1 H), 3.20 (d, J = 5.4 Hz, 1 H), 7.17–7.33 (m, 10 H); 13C NMR (75 MHz, CDCl3): δ = 28.77, 28.91, 31.52, 38.23, 39.43, 50.65, 53.99, 127.66, 128.25, 128.31, 128.47, 129.24, 129.39, 132.11, 135.03, 142.54, 169.85, 208.50; MS (EI): m/z = 300 (M+).3-Methyl-2,4,5-triphenylcyclopenta-2,4-dien-1-one (12h)Yield: 74.1 mg (23%); dark purple solid; 1H NMR (300 MHz, CDCl3): δ = 2.07 (s, 3 H), 7.11–7.45 (m, 15 H); 13C NMR (75 MHz, CDCl3): δ = 14.52, 124.61, 125.64, 127.27, 127.30, 127.93, 128.21, 128.49, 128.59, 128.62, 129.54, 129.82, 130.68, 131.34, 133.73, 154.12, 154.46, 200.42; MS (EI): m/z = 322 (M+).4-Methylene-2,3,5-triphenylcyclopent-2-en-1-one (12h′)Yield: 64.4 mg (20%); light purple solid; 1H NMR (300 MHz, CDCl3): δ = 4.34 (s, 1 H), 5.30 (s, 1 H), 5.44 (s, 1 H), 7.20–7.41 (m, 15 H); 13C NMR (75 MHz, CDCl3): δ = 56.05, 114.81, 127.20, 127.92, 128.09, 128.50, 128.58, 128.77, 128.94, 129.77, 130.66, 133.16, 137.69, 139.68, 148.91, 164.47, 202.67; MS (EI): m/z = 322 (M+).