Synlett 2016; 27(07): 1056-1060
DOI: 10.1055/s-0035-1561378
cluster
© Georg Thieme Verlag Stuttgart · New York

Synthesis of Supramolecular Iridium Catalysts and Their Use in Enantioselective Visible-Light-Induced Reactions

Alexander Böhm
Department Chemie and Catalysis Research Center (CRC), Technische Universität München, 85747 Garching, Germany   Email: thorsten.bach@ch.tum.de
,
Thorsten Bach*
Department Chemie and Catalysis Research Center (CRC), Technische Universität München, 85747 Garching, Germany   Email: thorsten.bach@ch.tum.de
› Author Affiliations
Further Information

Publication History

Received: 21 December 2015

Accepted after revision: 20 January 2016

Publication Date:
24 February 2016 (online)


Abstract

Iridium complexes were prepared which are covalently linked via a bipyridine ligand to a chiral octahydro-1H-4,7-methanoisoindol-1-one skeleton. The skeleton allows for two-point hydrogen bonding to prochiral lactams, which can be processed in iridium-catalyzed photochemical reactions. Attempts to use the iridium complexes in reactions, which typically involve photoinduced electron transfer, failed to provide the desired enantioselectivity. If employed as triplet sensitizers the complexes showed an improved performance and moderate enantioselectivities (up to 29% ee) were achieved in a photochemical epoxide rearrangement.

Supporting Information

Primary Data

 
  • References and Notes

    • 1a Ischay MA, Anzovino ME, Du J, Yoon TP. J. Am. Chem. Soc. 2008; 130: 12886
    • 1b Nicewicz DA, MacMillan DW. C. Science 2008; 322: 77

      Recent reviews:
    • 2a Schultz DM, Yoon TP. Science 2014; 343: 1239176/1
    • 2b Xi Y, Yi H, Lei A. Org. Biomol. Chem. 2013; 11: 2387
    • 2c Reckenthäler M, Griesbeck AG. Adv. Synth. Catal. 2013; 355: 2727
    • 2d Prier CK, Rankic DA, MacMillan DW. C. Chem. Rev. 2013; 113: 5322
    • 2e Zeitler K. Angew. Chem. Int. Ed. 2009; 48: 9785
    • 3a Lu Z, Yoon TP. Angew. Chem. Int. Ed. 2012; 51: 10329
    • 3b Zou Y.-Q, Duan S.-W, Meng X.-G, Hu X-Q, Gao S, Chen J.-R, Xiao W.-J. Tetrahedron 2012; 68: 6914
    • 3c Farney EP, Yoon TP. Angew. Chem. Int. Ed. 2014; 53: 793

      Recent reviews:
    • 4a Brimioulle R, Lenhart D, Maturi MM, Bach T. Angew. Chem. Int. Ed. 2015; 54: 3872
    • 4b Meggers E. Chem. Commun. 2015; 51: 3290
    • 5a Huo H, Shen X, Wang C, Zhang L, Röse P, Chen L.-A, Harms K, Marsch M, Hilt G, Meggers E. Nature (London, U.K.) 2014; 515: 100
    • 5b Huo H, Wang C, Harms K, Meggers E. J. Am. Chem. Soc. 2015; 137: 9551
    • 5c Wang C, Qin J, Shen X, Riedel R, Harms K, Meggers E. Angew. Chem. Int. Ed. 2016; 55: 685

      For previous work on chiral ruthenium complexes in enantioselective photochemistry, see:
    • 6a Hamada T, Ishida H, Usui S, Watanabe Y, Tsumura K, Ohkubo K. J. Chem. Soc., Chem. Commun. 1993; 909
    • 6b Ohkubo K, Hamada T, Ishida H. J. Chem. Soc., Chem. Commun. 1993; 1423

      For recent reviews on supramolecular and substrate-specific catalysis, see:
    • 7a Dydio P, Reek JN. H. Chem. Sci. 2014; 5: 2135
    • 7b Lindbäck E, Dawaigher S, Wärnmark K. Chem. Eur. J. 2014; 20: 13432
    • 7c Raynal M, Ballester P, Vidal-Ferran A, van Leeuwen PW. N. M. Chem. Soc. Rev. 2014; 43: 1660
    • 7d Carboni S, Gennari C, Pignatoro L, Piarulli U. Dalton Trans. 2011; 40: 4355

      Recent work:
    • 8a Frost JR, Huber SM, Breitenlechner S, Bannwarth C, Bach T. Angew. Chem. Int. Ed. 2015; 54: 691
    • 8b Zhong F, Pöthig A, Bach T. Chem. Eur. J. 2015; 21: 10310
  • 9 Fackler P, Berthold C, Voss F, Bach T. J. Am. Chem. Soc. 2010; 132: 15911

    • Selected contributions:
    • 10a Bauer A, Westkämper F, Grimme S, Bach T. Nature (London, U.K.) 2005; 436: 1139
    • 10b Müller C, Bauer A, Bach T. Angew. Chem. Int. Ed. 2009; 48: 6640
    • 10c Müller C, Bauer A, Maturi MM, Cuquerella MC, Miranda MA, Bach T. J. Am. Chem. Soc. 2011; 133: 16689
    • 10d Brimioulle R, Bach T. Science 2013; 342: 840
    • 10e Alonso R, Bach T. Angew. Chem. Int. Ed. 2014; 53: 4368
  • 11 Brotschi C, Mathis G, Leumann CJ. Chem. Eur. J. 2005; 11: 1911
    • 12a Sonogashira K, Tohda Y, Hagihara N. Tetrahedron Lett. 1975; 16: 4467
    • 12b Sonogashira K In Comprehensive Organic Synthesis . Vol. 3. Trost B. Pergamon Press; Oxford: 1991: 521-549
    • 12c Sonogashira K In Metal-Catalyzed Cross-Coupling Reactions . Diederich F, Stang PJ. Wiley-VCH; Weinheim: 1998: 203-229

      Additional reviews:
    • 13a Chinchilla R, Nájera C. Chem. Soc. Rev. 2011; 40: 5084
    • 13b Chinchilla R, Nájera C. Chem. Rev. 2007; 107: 874
  • 15 Lowry MS, Goldsmith JI, Slinker JD, Rohl R, Pascal RA, Malliaras GG, Bernhard S. Chem. Mater. 2005; 17: 5712
  • 16 Slinker JD, Gorodetsky AA, Lowry MS, Wang J, Parker S, Rohl R, Bernhard S, Malliaras GG. J. Am. Chem. Soc. 2004; 126: 2763
    • 17a Narayanam JM. R, Tucker JW, Stephenson CR. J. J. Am. Chem. Soc. 2009; 131: 8756
    • 17b Tucker JW, Nguyen JD, Narayanam JM. R, Krabbe SW, Stephenson CR. J. Chem. Commun. 2010; 46: 4985
  • 18 Flynn DL, Zelle RE, Grieco PA. J. Org. Chem. 1983; 48: 2424
  • 19 Heller ST, Natarajan SR. Org. Lett. 2006; 8: 2675
  • 20 Sevenard DV, Vorobyev M, Sosnovskikh VY, Wessel H, Kazakova O, Vogel V, Shevchenko NE, Nenajdenko VG, Lork E, Röschenthaler G.-V. Tetrahedron 2009; 65: 7538
  • 21 Cismesia MA, Yoon TP. Chem. Sci. 2015; 6: 5426
  • 22 Wang L, Su Y, Xu X, Zhang W. Eur. J. Org. Chem. 2012; 6606
  • 23 Maturi MM, Pöthig A, Bach T. Aust. J. Chem. 2015; 68: 1682
  • 24 Experimental Procedure for the Enantioselective Rearrangement of rac-13 To a solution of 10.0 mg (46.0 μmol, 1.0 equiv) 5-methoxy-3′,3′-dimethylspiro[indoline-3,2′-oxiran]-2-one (rac-13)23 in 4.6 mL degassed CH2Cl2, 2.72 mg (2.3 μmmol, 0.05 equiv), Ir cat. 5a was added, and the reaction mixture was irradiated for 2.5 h at –75 °C. After evaporation of the solvent, the crude product was purified by column chromatography (SiO2, 2.5 × 4 cm, pentane–EtOAc = 2:1 → 1:1) to obtain 9.3 mg (93%, 29% ee) (S)-3-acetyl-5-methoxy-3-methylindolin-2-one (14)23 as a colorless solid. 1H NMR (360 MHz, CDCl3, 300 K): δ = 7.79 (br s, 1 H, NH), 6.87 (d, 3 J = 8.4 Hz, 1 H, C7H), 6.82 (dd, 3 J = 8.4 Hz, 4 J = 2.5 Hz, 1 H, C6H), 6.73 (d, 4 J = 2.5 Hz, 1 H, C4H), 3.77 (s, 3 H, OCH3), 2.05 (s, 3 H, COCH3), 1.59 (s, 3 H, CH3) ppm. 13C NMR (125 MHz, CDCl3, 300 K): δ = 200.9 (s, COCH3), 177.6 (s, C2), 156.4 (s, C5), 134.0 (s, C7a), 131.4 (s, C3a), 114.2 (d, C6), 110.7 (d, C7), 110.6 (d, C4), 62.9 (s, C3), 55.9 (q, OCH3), 26.2 (q, COCH3), 19.1 (q, CH3) ppm.
  • 25 Maturi MM, Wenninger M, Alonso R, Bauer A, Pöthig A, Riedle E, Bach T. Chem. Eur. J. 2013; 19: 7461
  • 26 Maturi MM, Bach T. Angew. Chem. Int. Ed. 2014; 53: 7661