Recent Progress in Synthetic Applications of Hypervalent Iodine(III) Reagents

Abstract

Hypervalent iodine(III) compounds have found wide application in modern organic chemistry as environmentally friendly reagents and catalysts. Hypervalent iodine reagents are commonly used in synthetically important halogenations, oxidations, aminations, heterocyclizations, and various oxidative functionalizations of organic substrates. Iodonium salts are important arylating reagents, while iodonium ylides and imides are excellent carbene and nitrene precursors. Various derivatives of benziodoxoles, such as azidobenziodoxoles, trifluoromethylbenziodoxoles, alkynylbenziodoxoles, and alkenylbenziodoxoles have found wide application as group transfer reagents in the presence of transition metal catalysts, under metal-free conditions, or using photocatalysts under photoirradiation conditions. Development of hypervalent iodine catalytic systems and discovery of highly enantioselective reactions using chiral hypervalent iodine compounds represent a particularly important recent achievement in the field of hypervalent iodine chemistry. Chemical transformations promoted by hypervalent iodine in many cases are unique and cannot be performed by using any other common, non-iodine-based reagent. This review covers literature published mainly in the last 7-8 years, between 2016 and 2024.

Scheme 1. Preparation of (Difluoroiodo)arenes 2 with Ortho Substitution

Scheme 2. Preparation of (Difluoroiodo)arenes 4 Using AgF₂

Scheme 3. Preparation of p-NO₂C₆H₄IF(OTf) 6

Scheme 4. Fluoro Sulfoximidations of Styrenes 9

Scheme 5. Preparation of Phosphate Fluorides 12

Scheme 6. Proposed Reaction Mechanism of Fluorination of Phosphine Oxide 11

Scheme 7. Fluorination Reaction of Alkylsilanes 16

Scheme 8. gem-Difluorination Reaction of Hydrazones 19

Scheme 9. Preparation of α-(Difluoromethyl)styrenes 22

Scheme 10. Synthesis of β-Difluorinated Alkylborons 25 from Styrenes 23

Scheme 11. Proposed Mechanism of Formation of Products 25 from Styrenes 23

Scheme 12. Preparation of Difluorinated Alkylidenecyclobutanes 31

Scheme 13. Proposed Mechanism of Formation of Difluorinated Alkylidenecyclobutanes 31

Scheme 14. Synthesis of μ-Fluorido-Diiron(III) Complex 38 and Monomeric Product 39

Scheme 15. Fluorocarbonylation of Unactivated Alkenes 40

Scheme 16. Reaction of β-Sulfidocarbonyl Compounds 43 with (Dichloroiodo)benzene 44

Scheme 17. Preparation of Tetracoordinated Hypervalent Iodine Compound 46

Scheme 18. gem-Dichlorination of Aromatic Isonitriles 47 Using 44

Scheme 19. Proposed Mechanism of gem-Dichlorination Reaction of Aromatic Isonitriles 47

Scheme 20. Reaction of Methyl o-Alkynylbenzoates 51 with Reagent 44

Scheme 21. Proposed Mechanism of Chlorolactonization of Methyl o-Alkynylbenzoates 51

Scheme 22. Oxidative Cyclization Reaction of Alkynone (Z)-o-Methyl Oximes 56

Scheme 23. gem-Chlorosulfurization of p-Toluenesulfonyl Difluorodiazoethane 58

Scheme 24. Preparation of 2-Amino-1,3-selenazoles 61

Scheme 25. Preparation of Thiocyanated Isobenzofuranones 63

Scheme 26. Proposed Mechanism of Formation of Thiocyanated Isobenzofuranones 63

Scheme 27. Reaction of 4-Methylquinoline 68 and Alcohols 69 with Reagent 44 under Blue-LED

Scheme 28. Preparation of Complex 72 using Reagent 44

Scheme 29. Photolysis of Complex 72

Scheme 30. Reaction of Gold Complexes 74 with Reagent 44

Scheme 31. Preparation of Carbazole Compounds 78 from Anilines 77

Scheme 32. Preparation of N-Acetoxyamides 80 from Aldoximes 79

Scheme 33. Oxidative Rearrangement of Secondary Amines 81

Scheme 34. Proposed Mechanism for the Formation of 82

Scheme 35. DIB-Mediated Oxidative Cleavage Reaction of 5-Aminopyrazoles 85

Scheme 36. DIB-Mediated Oxidative Ring-Expansion Reaction of 2-Aminobenzothiazoles 87

Scheme 37. Denitrogenation of N-Arylsulfonylhydrazones 91 Using DIB 24

Scheme 38. Cross-Coupling Reaction of N-Methoxyamide 93 and Benzotriazole 94

Scheme 39. Preparation of Cycloheptatriene-Fused Lactam 97

Scheme 40. Cycloaddition Reaction of Indoles 99

Scheme 41. Proposed Mechanism for Cycloaddition Reaction of Compounds 98 and 99 Using Reagent 24

Scheme 42. Preparation of Sulfonimidamides 105

Scheme 43. Preparation of Sulfinimidate Esters 108

Scheme 44. Allylic C–H Amination of 109

Scheme 45. Proposed Mechanism of Product 112 Formation

Scheme 46. Preparation of 5,5-Disubstituted Oxazolidine-2,4-dione 117

Scheme 47. Proposed Mechanism for the Conversion of Compound 116 to Product 117

Scheme 48. Sigmatropic Rearrangement Reactions Using DIB 24

Scheme 49. Sigmatropic Rearrangement Reaction Using PIFA 136

Scheme 50. Proposed Mechanism α-Arylation of Ketone 135

Scheme 51. Preparation of Binaphthyl Compounds 142

Scheme 52. α-Tosyloxylation of α,β-Unsaturated Compounds 144

Scheme 53. Proposed Mechanism of α-Tosyloxylation Reaction of Compounds 144

Scheme 54. Functionalization of 8-Aminoquinolinamides 148 Using (Diacyloxyiodo)benzene Reagents

Scheme 55. Halocyclization of Sulfoximimes 153 Using DIB/KI Combination

Scheme 56. Cyclizations of Amino Derivatives Using DIB 24 with an Additive

Scheme 57. β C–H Amination of Imidate 165

Scheme 58. Generation of Carbon Radicals 170 via HAT Reaction

Scheme 59. Hydrodifluoromethylation of Alkenes 171

Scheme 60. PIFA-Mediated Cascade Reaction of Phenolic Compound 174

Scheme 61. PIFA- and I₂-Meditated Cyclization of Amines 176

Scheme 62. PIFA-Meditated Oxidative Dimerization of 2H-Indazole 178

Scheme 63. Palladium-Catalyzed Cyclization of Alkenols 180

Scheme 64. Palladium-Catalyzed Cyclizations of Benzylamide 183

Scheme 65. Ring Rearrangement of 1,3-Azasilinyl-4-Epoxides 186

Scheme 66. Copper-Catalyzed Coupling Reaction Between 188 and 189

Scheme 67. Preparation of Gold(III) Complexes from 191 Using DIB 24

Scheme 68. Photocatalyst-Mediated Decarboxylative Methylation of 194

Scheme 69. Preparation of Oxo-Spiro Compounds 197 from 196 Using PhIO 17

Scheme 70. Synthesis of Sulfonimidates 199 from Sulfinamides 198 and PhIO in the Presence of Alcohols

Scheme 71. Preparation of Monofluorinated Five-Membered Ring-Fused Oxazolines

Scheme 72. Synthesis of 10-Azacorroles 205

Scheme 73. Lactonization Reaction of 206 with PhIO in Alcohol Solutions

Scheme 74. Asymetric Epoxidation of Alkenes 208

Scheme 75. Synthesis of 4-NO₂C₆H₄I(NTf₂)₂212

Scheme 76. Amination of Indole Compounds 213

Scheme 77. Selective C–H Amidation of Indole 215

Scheme 78. Preparation of NTs₂-Substituted 2,5-Dihydrofuran 218

Scheme 79. Proposed Reaction Mechanism for the Synthesis of 218 from 217

Scheme 80. Preparation of (PhSO₂)₂N-Substituted Alkynes 222 from Alkynes 221

Scheme 81. Oxidative Cyclization of N-Allylamides 223

Scheme 82. Preparation of Ag(II) Complex 226

Scheme 83. Synthesis of Aminocyclopropanes 228 from Allenes 227

Scheme 84. Selective Benzylic C–H Amination of 229

Scheme 85. Preparation of Hydrazinium Tosylate Salts 232

Scheme 86. [2 + 2 + 1] Cycloaddition Reaction Using C₆F₅INTs

Scheme 87. Photoinduced C–H Amination of Mesitylene 235 Using Reagent 236

Scheme 88. Steps in the Formation of Tetrameric Molecule 240

Scheme 89. Nitrooxylation of Cyclopropyl Trimethylsilyl Ether 242

Scheme 90. Difunctionalization of 2H-Indazole 245

Scheme 91. Synthesis of Carbazolones 249 from Exocyclic β-Enaminone 250

Scheme 92. α-Arylation of Ketones 254 via Enolonium Species 252

Scheme 93. Cyclization of Propargylic Alcohols 255 to Naphthyl(aryl)iodonium Triflates 256

Scheme 94. Cyanotriflation of Alkynes 257

Scheme 95. Preparation of p-NO₂C₆H₄I(OTf)₂259

Scheme 96. Reaction of Triphenylmethane 260 with p-NO₂C₆H₄I(OTf)₂259

Scheme 97. Trifluoromethylation-Cyclization of Isocyanides 263 with PhI(CF₃)Cl 262

Scheme 98. Synthesis of N-Trifluoromethyl Amidines 266 from Nitriles Using PhICF₃Cl 262

Scheme 99. Hydrotrifluoromethylation of Ynamides 268

Scheme 100. Regio- and Stereoselective Perfluoropropylation of Alkyne 270

Scheme 101. Diazirination of Carbohydrazides 273

Scheme 102. α-Diazomethylation of Silyl Enol Ethers 277

Scheme 103. ortho-Diazomethylation of Aromatic Tertiary Amines 277

Scheme 104. [3 + 3] Annulation of Enaminones 282 Using Iodonium Ylide 281

Scheme 105. Cyclization of Aromatic Tertiary Amines 284 Using Iodonium Ylide 285

Scheme 106. Unactivated C(sp³)–H Bond Insertion Reaction of Pyridines 287

Scheme 107. Copper-Catalyzed [2,3]-Sigmatropic Rearrangement

Scheme 108. Radiofluorination of Iodonium Ylide 294

Scheme 109. NHC-Catalyzed Synthesis of Ynones 298 from Alkynyliodonium Salts and Aldehydes

Scheme 110. C₂ Generation and Trapping Reaction in the Presence of 9,10-Dihydroanthracene 300

Scheme 111. Reaction of Alkynyliodonium Salt 303 with N-(Acyloxy)sulfonamides 304

Scheme 112. Synthesis of Indoles 308 from Arylhydroxylamines 306 and Vinyliodonium Salt 307

Scheme 113. Aziridination of Amines 311 Using Vinyliodonium Salt 310

Scheme 114. N-Alkylations of Anilines 314 Using Alkyliodonium Salt 313

Scheme 115. Synthesis of Anilines 317 from Diaryiodonium Salts 316

Scheme 116. 1,4-Double Cycloaddition of Diaryliodonium Triflate 318

Scheme 117. Intramolecular Fluorination of Carbamates 321 Using Fluorobenziodoxole 322

Scheme 118. Ring Expansion Fluorination of Cyclopropanes 324 Using Reagent 325

Scheme 119. α-Functionalization of 2-Pyridyl Ketones 327

Scheme 120. Dichlorination of Aromatic Allenes 329 Using Chlorobenziodoxole 330

Scheme 121. Disulfonation of Terminal Alkynes 332

Scheme 122. Ligand Exchange Reactions of Chlorobenziodazole 336

Scheme 123. C–H Acyloxylation of Sulfides 339

Scheme 124. Photocatalyst-Induced Intramolecular Cyclization of 342

Scheme 125. Photocatalyst Mediated C–H Alkylation of 4-Chloroquinoline 346

Scheme 126. Radical Reactions of Oxamic Acid 348 Using Acetoxybenziodoxole 344

Scheme 127. Intramolecular Cyclization of Cyclic Alcohols 353

Scheme 128. Cyanation of Alkyltrifluoroborates 355

Scheme 129. Azido-Alkynylation of Alkenes 359

Scheme 130. Dearomatic Azidation-Cyclization of Triptamines 362

Scheme 131. Selective C–H Azidation of Indoles 365

Scheme 132. Selective C–H Chlorination of Tertiary Alkyl Compounds 367

Scheme 133. Bifunctionalization of Styrenes 369 Using 1-Sulfoximidoyl-1,2-benziodoxoles 370

Scheme 134. Alkylamination of Styrenes 372

Scheme 135. Preparation of Aminoketones 379 from Cyclic Alcohols 376 with Imides 378

Scheme 136. C–H Insertion Amination Reaction of Thiophenes 381

Scheme 137. Trifluoromethylation of Alcohols Using Cyclic Iodine(III) Reagent 384

Scheme 138. Cyclotrifluoromethylation of Isocyanate Substrates Using 387

Scheme 139. Bifunctionalization of Styrene 396

Scheme 140. Bifunctionalization of Alkynes 403

Scheme 141. C–H Trifluoromethylation of Pyrrolidine 405

Scheme 142. C–H Perfluoroalkylation of Aromatic Compounds 407 and 409

Scheme 143. Asymmetric α-Cyanation of β-Keto Esters 412

Scheme 144. Decarboxylative Cyanation of Carboxylic Acids 415

Scheme 145. Desilylative Cyanation of Amines 417

Scheme 146. Synthesis of Dibenzotellurophene 420

Scheme 147. Preparation of Polycyclic N-Heteroarenes 422

Scheme 148. Palladium-Catalyzed Enantioselective Double Carbonylation

Scheme 149. meta-Selective O-Arylation of Cyclic Iodonium Salt 419

Scheme 150. Alkynylcarbonylation of Alkenes 428

Scheme 151. Synthesis of Propargylic Esters 433 from Diazo Compounds 431

Scheme 152. Preparation of Diynamides 436 from Amines 435 Using Reagent 434

Scheme 153. Synthesis of Alkenylbenziodoxoles 439 from Alkynylbenziodoxoles 437

Scheme 154. Alkenylation of Thiols 441 Using Alkenylbenziodoxoles 440

Scheme 155. Preparation of Pseudocyclic Alkenyliodonium Triflates 445

Scheme 156. Synthesis of Pseudocyclic Iodine(III) Compounds 447

Scheme 157. Synthesis of Pseudocyclic Iodine(III) Compound 449 with 1H-Pyrazole Rings

Scheme 158. Preparation of Cyclopropenium Salts 452 from Alkynes 450

Scheme 159. Synthesis of Arylsulfonium Triflates 455 from Sulfides 454

Scheme 160. Catalytic Difluorination of Enynes 456

Scheme 161. Cycloisomerization-Arylation of N-Propargyl Amides 458

Scheme 162. Decarboxylative Amination of Carboxylic Acids 461

Scheme 163. Hypervalent Iodine-Mediated Intramolecular Cyclization of 463

Scheme 164. Catalytic Intramolecular Cyclofluorination of Benzamides 465 and 467

Scheme 165. Catalytic α-Tosyloxylation of Ketones 469

Scheme 166. α-Amidation of 1,3-Dicarbonyl Compounds 471

Scheme 167. Electrocatalytic Diacetoxylation of Alkenes 473