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Review
. 2016 Sep 14;116(17):10035-74.
doi: 10.1021/acs.chemrev.6b00018. Epub 2016 Apr 25.

Dual Catalysis Strategies in Photochemical Synthesis

Kazimer L Skubi  1 , Travis R Blum  1 , Tehshik P Yoon  1
Affiliations
Review

Dual Catalysis Strategies in Photochemical Synthesis

Kazimer L Skubi et al. Chem Rev. .

Abstract

The interaction between an electronically excited photocatalyst and an organic molecule can result in the genertion of a diverse array of reactive intermediates that can be manipulated in a variety of ways to result in synthetically useful bond constructions. This Review summarizes dual-catalyst strategies that have been applied to synthetic photochemistry. Mechanistically distinct modes of photocatalysis are discussed, including photoinduced electron transfer, hydrogen atom transfer, and energy transfer. We focus upon the cooperative interactions of photocatalysts with redox mediators, Lewis and Brønsted acids, organocatalysts, enzymes, and transition metal complexes.

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Conflict of interest statement

The authors declare no competing financial interest.

Figures

Scheme 1
Scheme 1. Mechanisms of Homogeneous Photocatalysis
Figure 1
Figure 1
Chemical structures of common photocatalysts.
Figure 2
Figure 2
Photoinduced electron transfer (PET).
Figure 3
Figure 3
Direct and secondary quenching for an oxidative reaction.
Figure 4
Figure 4
Redox mediation of an oxidative transformation.
Figure 5
Figure 5
Common photocatalyst/redox mediator pair 9,10-dicyanoanthracene (DCA) and biphenyl (BP).
Scheme 2
Scheme 2. Redox-Mediated Epoxide Photooxygenation
Scheme 3
Scheme 3. Redox-Mediated Cyclopropane Photooxygenation
Scheme 4
Scheme 4. Effect of Redox Mediator on Ion Pair Separation for Cyclopropane Isomerization and Photooxygenation
Oxidation potentials vs Ag/AgClO4 in MeCN. Oxidation potential of cyclopropane 25.
Scheme 5
Scheme 5. Dimerization of Phenyl Vinyl Ether by Redox-Mediated PET
Scheme 6
Scheme 6. Alkene Photooxygenation and Trapping
Scheme 7
Scheme 7. [2+2] Cycloaddition of Styrenes by PET
Scheme 8
Scheme 8. Photooxidative Radical Cation Cascade Employing Redox Mediation
Scheme 9
Scheme 9. Acylation of C60 Using PET and Redox Mediation
Scheme 10
Scheme 10. Oxidative Destannylation and Radical Addition
Scheme 11
Scheme 11. Oxidative Deselenation and Nucleophilic Trapping
Scheme 12
Scheme 12. Photooxidative Desilylation and Radical Addition
Scheme 13
Scheme 13. Radical Thiol–Ene Reaction with Anilines as Redox Mediators
Scheme 14
Scheme 14. Oxidative Fragmentation of α,β Amino Alcohols
Scheme 15
Scheme 15. Methylene Cyclopropane Rearrangement and Cycloadditions
Scheme 16
Scheme 16. Effect of Redox Mediator on Chemoselectivity of a Photooxidative Azoalkane Rearrangement
Scheme 17
Scheme 17. Oxidative Cage Ketone Rearrangement and Influence of Redox Mediators
Oxidation potentials vs SCE in MeCN.
Scheme 18
Scheme 18. Redox Mediation Applied to Benzoquinone Reduction
Scheme 19
Scheme 19. Reductive Mediation Combined with Phase Transfer Catalysis
Scheme 20
Scheme 20. Effect of Redox Mediators on Photoreductive Cycloreversion
Scheme 21
Scheme 21. Reductive Dehalogenation Using a CoII Redox Mediator
Scheme 22
Scheme 22. Photoreduction of Fumarate Promoted by Lewis Acid Coordination
Scheme 23
Scheme 23. Reductive Deoxygenation by Lewis Acid-Promoted PET
Scheme 24
Scheme 24. Effect of Mg2+ on Photocatalytic Alkene Reduction
Reduction potential vs Ag/AgNO3 in MeCN. The listed values are in the absence of Mg2+. The parenthetical values are when Mg2+ is added.
Scheme 25
Scheme 25. Photoreductive Substitution with Mg(ClO4)2 Cocatalyst
Scheme 26
Scheme 26. Photoreductive [2+2] Cycloaddition with LiBF4
Scheme 27
Scheme 27. Enantioselective [2+2] Cycloaddition Using a Chiral Lewis Acid Cocatalyst
Scheme 28
Scheme 28. Ru(bpy)3Cl2/Mg(ClO4)2-Catalyzed [4+2] Bis(enone) Cycloaddition
Scheme 29
Scheme 29. Photoreductive [3+2] Cycloadditions by Lanthanide Cocatalysis
Scheme 30
Scheme 30. Reductive Chalcone Dimerization Catalyzed by Sm3+ and Ru(bpy)3(PF6)2
Scheme 31
Scheme 31. Lewis Acid-Templated Photocatalytic Alcohol Oxidation
Scheme 32
Scheme 32. Lewis Acid Accelerated Cyclopropane Photooxidation by BET Suppression
Scheme 33
Scheme 33. Effect of Mg2+ Binding of Flavin Photoredox Properties
Redox potentials determined indirectly on the basis of the oxidation potentials of various arenes vs SCE in MeCN. See ref (169) for details. The listed values are in the absence of Mg2+. The parenthetical values are when Mg2+ is added.
Scheme 34
Scheme 34. Lewis Acid Accelerated Addition after PET
Scheme 35
Scheme 35. Radical Cation Cascade Promoted by Lewis Acid Activation
Scheme 36
Scheme 36. Enantioselective Lewis Acid-Catalyzed Addition of Radical Generated by PET
Scheme 37
Scheme 37. Reductive Cyclization of Ketones by PCET
Scheme 38
Scheme 38. Reductive Cyclization of Bis(enones)
Scheme 39
Scheme 39. Effect of Brønsted Acid on Rates of Electron Transfer to α-Bromoketones
Scheme 40
Scheme 40. PCET and Amide Cyclization
Scheme 41
Scheme 41. Brønsted Acid-Catalyzed Addition of PET-Generated α-Amino Radicals to Enones
Scheme 42
Scheme 42. Enantioselective Radical Coupling Reaction Using Chiral Ion Pairing
Scheme 43
Scheme 43. Nitroarene Reduction and Post-PET Cyclization
Scheme 44
Scheme 44. Aldehyde α-Alkylation by Tandem Photo-/Organocatalysis
Scheme 45
Scheme 45. Aldehyde β-Arylation by Tandem Photo-/Organocatalysis
Scheme 46
Scheme 46. Formal β-Mannich Reaction Using Several Types of Cocatalysis
Scheme 47
Scheme 47. Aldehyde β-Alkylation
Scheme 48
Scheme 48. Oxidation of THIQ and Interception by an Organocatalytic Nucleophile
Scheme 49
Scheme 49. Photooxidative Cyclization Merged with HAT Catalysis
Scheme 50
Scheme 50. Alkene–Acid Coupling by Photocatalysis/HAT Catalysis
Scheme 51
Scheme 51. Aromatic C–H Amination Using Photocatalysis and TEMPO as an HAT Catalyst
Scheme 52
Scheme 52. Benzylic C–H Arylation by Photo/HAT Cocatalysis
Scheme 53
Scheme 53. C–H Arylation of Simple Alkenes
Scheme 54
Scheme 54. Alkene–Alcohol Coupling Catalyzed by Site-Selective HAT
Scheme 55
Scheme 55. Umpolung Reactivity Using Dual Photo/NHC Catalysis
Scheme 56
Scheme 56. Photocatalytic Carboxylic Acid Dehydration with Acyl Transfer Cocatalysis
Scheme 57
Scheme 57. Dual Halide/Photoredox Catalysis
Figure 6
Figure 6
Common modes of tandem transition metal/photocatalysis.
Scheme 58
Scheme 58. Oxidative Heck Reaction Employing Photocatalytic Palladium Turnover
Scheme 59
Scheme 59. Nickel-Catalyzed Cross Coupling Enabled by Photocatalysis
Scheme 60
Scheme 60. Decarboxylative Allylation Using Palladium and Photocatalysis
Scheme 61
Scheme 61. Oxidation of THIQ and Trapping with Metal Acetylides
Scheme 62
Scheme 62. Photocatalytic Diazonium Reduction and Palladium Catalysis with Resulting Aryl Radical
Scheme 63
Scheme 63. Tandem Gold/Photocatalyzed Cyclization/Arylation Reaction
Scheme 64
Scheme 64. Tandem Gold/Photocatalyzed Alkene Functionalization
Scheme 65
Scheme 65. Nickel-Catalyzed Cross-Coupling Employing Photocatalytically Generated Benzylic Radicals
Scheme 66
Scheme 66. Nickel-Catalyzed Cross Coupling Using Photocatalytic Decarboxylation To Generate α-Amino Radicals
Scheme 67
Scheme 67. Aryl Trifluoromethylation Using Tandem Copper/Photocatalysis
Scheme 68
Scheme 68. Alkane Oxidation by Photogenerated Hydroxyl Radical
Scheme 69
Scheme 69. Dehydrogenative Cross Coupling Using Both Cobalt and Photocatalysis
Scheme 70
Scheme 70. Enzymatic/Photocatalytic Ketone Reduction
Scheme 71
Scheme 71. Benzophenone/Copper Tandem Catalysis for Alkane Dehydrogenation
Scheme 72
Scheme 72. Alcohol Dehydrogenation by Tandem Polyoxotungstate and Cobaloxime Catalysis
Scheme 73
Scheme 73. Dexter Mechanism for Triplet Energy Transfer
Scheme 74
Scheme 74. Tandem Allylic Oxidation and Alkene Epoxidation
Scheme 75
Scheme 75. Asymmetric Epoxidation Applied in Dual Photo/Transition Metal Catalysis
Scheme 76
Scheme 76. Aerobic Alkene Dihydroxylation via Photocatalytic Generation of Selenoxides
Scheme 77
Scheme 77. Ullmann-Type Coupling Using Ir/Cu Dual Catalysis
Scheme 78
Scheme 78. Enantioselective Photooxygenation of Tryptamine
Scheme 79
Scheme 79. Aldehyde α-Oxygenation by Dual Enamine and Photocatalysis
Scheme 80
Scheme 80. Asymmetric Phase Transfer Cocatalysis Applied to Photochemical Enolate Oxidation
Scheme 81
Scheme 81. Arene C–H Amination Using Triplet Energy Transfer and Brønsted Acid Cocatalysis
Scheme 82
Scheme 82. Silyl Enol Ether Protonation by Photosensitized Naphthol
See this image and copyright information in PMC

References

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