Metal-free, cooperative asymmetric organophotoredox catalysis with visible light

Angewandte Chemie - International Edition

Volumn 50, Issue 4, 2011, Pages 951-954

  Neumann, Matthias ^a   Füldner, Stefan ^a   König, Burkhard ^a   Zeitler, Kirsten ^a  

^a UNIVERSITY OF REGENSBURG   (Germany)

Author keywords

asymmetric alkylation; cooperative catalysis; organocatalysis; photocatalysis; xanthene dyes

Indexed keywords

ALKYLATION; LIGHT; METAL COMPLEXES; PHOTOCATALYSIS; XANTHENES;

ASYMMETRIC ALKYLATION; COOPERATIVE CATALYSIS; GREEN LIGHT; METAL FREE; ORGANOCATALYSIS; ORGANOCATALYTIC; VISIBLE LIGHT; XANTHENE DYES;

CATALYSIS;

EID: 78751510344     PISSN: 14337851     EISSN: 15213773     Source Type: Journal    
DOI: 10.1002/anie.201002992     Document Type: Article

References (79)

1. For recent reviews on organocatalysis, see
2. A. Dondoni, A. Massi, Angew. Chem. 2008, 120, 4716-4739
3. Angew. Chem. Int. Ed. 2008, 47, 4638-4660
4. D. W. C. MacMillan, Nature 2004, 346, 1007-1249
5. J. Seayad, B. List, Org. Biomol. Chem. 2005, 3, 719-724
6. A. Berkessel, H. Gröger, Asymmetric Organocatalysis, Wiley-VCH, Weinheim, 2005
7. P. I. Dalko, Enantioselective Organocatalysis, Wiley-VCH, Weinheim, 2007.
8. For some selected recent applications, see
9. H. Ishikawa, T. Suzuki, Y. Hayashi, Angew. Chem. 2009, 121, 1330-1333
10. Angew. Chem. Int. Ed. 2009, 48, 1304-1307
11. B.-C. Hong, P. Kotame, C.-W. Tsai, J.-H. Liao, Org. Lett. 2010, 12, 776-779
12. P. Jakubec, D. M. Cockfield, D. J. Dixon, J. Am. Chem. Soc. 2009, 131, 16632-16633; Review
13. R. Marcia de Figueiredo, M. Christmann, Eur. J. Org. Chem. 2007, 2575-2600.
14. C. Grondal, M. Jeanty, D. Enders, Nat. Chem. 2010, 2, 167-178
15. D. Enders, C. Grondal, M. R. M. Hüttl, Angew. Chem. 2007, 119, 1590-1601
16. Angew. Chem. Int. Ed. 2007, 46, 1570-1581
17. L. F. Tietze, G. Brasche, K. Gerike, Domino Reactions in Organic Chemistry, Wiley-VCH, Weinheim, 2006.
18. J. Zhou, Chem. Asian J. 2010, 5, 422-434
19. C. Zhong, X. Shi, Eur. J. Org. Chem. 2010, 2999-3025
20. Z. Shao, H. Zhang, Chem. Soc. Rev. 2009, 38, 2745-2755.
21. K. Zeitler, Angew. Chem. 2009, 121, 9969-9974
22. Angew. Chem. Int. Ed. 2009, 48, 9785-9789
23. D. Ravelli, D. Dondi, M. Fagnoni, A. Albini, Chem. Soc. Rev. 2009, 38, 1999-2011.
24. M. Ishikawa, S. Fukuzumi, J. Am. Chem. Soc. 1990, 112, 8864-8870
25. S. Fukuzumi, S. Mochizuki, T. Tanaka, J. Chem. Soc. Perkin Trans. 2 1989, 1583-1589
26. S. Fukuzumi, S. Mochizuki, T. Tanaka, J. Phys. Chem. 1990, 94, 722-726
27. G. Pandey, S. Hajra, Angew. Chem. 1994, 106, 1217-1218
28. Angew. Chem. Int. Ed. Engl. 1994, 33, 1169-1171
29. G. Pandey, M. K. Ghorai, S. Hajra, Pure Appl. Chem. 1996, 68, 653-658.
30. A. G. Condie, J. C. González-Gõmez, C. R. J. Stephenson, J. Am. Chem. Soc. 2010, 132, 1464-1465
31. J. W. Tucker, J. M. R. Narayanam, S. W. Krabbe, C. R. J. Stephenson, Org. Lett. 2010, 12, 368-371
32. J. Du, T. P. Yoon, J. Am. Chem. Soc. 2009, 131, 14604-14605
33. M. A. Ischay, M. E. Anzovino, J. Du, T. P. Yoon, J. Am. Chem. Soc. 2008, 130, 12886-12887
34. T. Koike, M. Akita, Chem. Lett. 2009, 38, 166-167.
35. D. A. Nicewicz, D. W. C. MacMillan, Science 2008, 322, 77-80
36. D. A. Nagib, M. E. Scott, D. W. C. MacMillan, J. Am. Chem. Soc. 2009, 131, 10875-10877.
37. For a pioneering example in intramolecular organocatalytic asymmetric alkylation
38. N. Vignola, B. List, J. Am. Chem. Soc. 2004, 126, 450 α451; for intramolecular examples within domino processes, see
39. D. Enders, C. Wang, J. W. Bats, Angew. Chem. 2008, 120, 7649-7653
40. Angew. Chem. Int. Ed. 2008, 47, 7539-7542
41. H. Xie, L. Zu, H. Li, J. Wang, W. Wang, J. Am. Chem. Soc. 2007, 129, 10886-10894
42. R. Rios, H. Sundén, J. Vesely, G.-L. Zhao, P. Dziedzic, A. Cõrdova, Adv. Synth. Catal. 2007, 349, 1028-1032.
43. For recent examples relying on the use of stabilized carbocations as compatible electrophiles
44. R. R. Shaikh, A. Mazzanti, M. Petrini, G. Bartoli, P. Melchiorre, Angew. Chem. 2008, 120, 8835-8838
45. Angew. Chem. Int. Ed. 2008, 47, 8707-8710
46. P. G. Cozzi, F. Benfatti, L. Zoli, Angew. Chem. 2009, 121, 1339-1342
47. Angew. Chem. Int. Ed. 2009, 48, 1313-1316
48. L. Zhang, L. Cui, X. Li, J. Li, S. Luo, J.-P. Cheng, Chem. Eur. J. 2010, 16, 2045-2049.
49. For a recent review on catalytic asymmetric α-alkylations, see:, A.-N. Alba, M. Viciano, R. Rios, ChemCatChem 2009, 1, 437-439.
50. 0), which should facilitate cleavage of the C-Hal bond to furnish the electron-deficient radical by SET to the activated α-bromocarbonyl compound.
51. J. M. R. Narayanam, J. W. Tucker, C. R. J. Stephenson, J. Am. Chem. Soc. 2009, 131, 8756-8757.
52. M. Zhang, C. Chen, W. Ma, J. Zhao, Angew. Chem. 2008, 120, 9876-9879
53. Angew. Chem. Int. Ed. 2008, 47, 9730-9733.
54. J. Moser, M. Grätzel, J. Am. Chem. Soc. 1984, 106, 6557 α6564; for recent reviews, see
55. Y. Ooyama, Y. Harima, Eur. J. Org. Chem. 2009, 2903-2934
56. A. Mishra, M. K. R. Fischer, P. Bäuerle, Angew. Chem. 2009, 121, 2510-2536
57. Angew. Chem. Int. Ed. 2009, 48, 2474-2499.
58. For a better comparison all values are reported in reference to the SCE electrode. If necessary the original values were converted according to:, V. V. Pavlishchuk, A. W. Addison, Inorg. Chim. Acta 2000, 298, 97-102; see the Supporting Information for details and references.
59. The reaction can also be conducted under the light of a 23 W fluorescent bulb; see also Ref. [21]. High-power LEDs applied for photocatalysis (e.g. Philips LUXEON Rebel 1W) show high color fidelity (Î=530±10 nm) and a radiometric power of approximately 145 lm.
60. See the Supporting Information for details.
61. In a number of comparative studies using xanthene dyes as photoinitiators eosin Y has been shown to counterbalance high reactivity with sufficient stability. For selected examples, see
62. T. Lazarides, T. McCormick, P. Du, G. Luo, B. Lindley, R. Eisenberg, J. Am. Chem. Soc. 2009, 131, 9192-9194
63. M. V. Encinas, A. M. Rufs, S. G. Bertolotti, C. M. Previtali, Polymer 2009, 50, 2762-2767
64. S. H. Lee, D. H. Nam, C. B. Park, Adv. Synth. Catal. 2009, 351, 2589-2594.
65. -1): $2.66 (based on Sigma-Aldrich and Acros prices for 2010).
66. 2+ conditions (see Table 3, entry 3).
67. M. Amatore, T. D. Beeson, S. P. Brown, D. W. C. MacMillan, Angew. Chem. 2009, 121, 5223-5226
68. Angew. Chem. Int. Ed. 2009, 48, 5121-5124.
69. For the seminal report on enantioselective trifluormethylation of aldehydes by photoredox catalysis see Ref. [8b]. A mechanistically different nonphotolytic (closed-shell) approach merging organocatalysis with iodonium salts was published only recently:, A. E. Allen, D. W. C. MacMillan, J. Am. Chem. Soc. 2010, 132, 4986-4987.
70. The efficient formation of long-lived triplet states following photoexcitation through ISC is facilitated by the heavy-atom effect (increased spin-orbit mixing; Br substituents)
71. T. Shimidzu, T. Iyoda, Y. Koide, J. Am. Chem. Soc. 1985, 107, 35-41
72. D. C. Neckers, O. M. Valdes-Aguilera, Adv. Photochem. 1993, 18, 315-394.
73. 3 EY, see Ref. [19a]. For selected recent examples on reductive and oxidative quenching, see
74. F. Labat, I. Ciofini, H. P. Hratchian, M. Frisch, K. Raghavachari, C. Adamo, J. Am. Chem. Soc. 2009, 131, 14290-14298
75. M. A. Jhonsi, A. Kathiravan, R. Renganathan, J. Mol. Struct. 2009, 921, 279-284.
76. +)=+0.79 V vs. SCE; see the Supporting information for details.
77. Remarkably, in contrast to most photocatalytic processes MacMillan's system does not require any sacrificial oxidant or reductant by its design; both oxidation and reduction steps are productive and lead to the formation of the desired product.
78. For a recent discussion on the normalization of photocatalytic reactions, see:, T. Maschmeyer, M. Che, Angew. Chem. 2010, 122, 1578-1582
79. Angew. Chem. Int. Ed. 2010, 49, 1536-1539.