High-Yielding One-Pot Synthesis of

Diaryliodonium Triflates from Arenes and

Iodine or Aryl Iodides

Marcin Bielawski and Berit Olofsson*

Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University,

SE-106 91 Stockholm, Sweden.

berit@organ.su.se

SUPPORTING INFORMATION

1. General experimental conditions S2

2. Synthesis of iodonium salts 3 S2-S3

3. Analytical data of salts 3 S4-S7

4. NMR spectra of salts 3 S7-S26

S1

1. General experimental conditions: NMR spectra were recorded using DMSO-d6, CDCl3 or MeOD-d4 as solvent. DMSO-d6 was the solvent of choice in most cases, as all salts were soluble. Chemical shifts are given in ppm relative to TMS for CDCl3, the residual peak of DMSO (1H NMR δ 2.50, 13C NMR 39.52) or MeOD (1H NMR δ 3.31, 13C NMR 49.00) as internal standard, with multiplicity (br=broad, s=singlet, d=doublet, t=triplet, q=quartet, m=multiplet), integration and coupling constants (Hz). In the IR spectra, only the strongest/structurally most important peaks (n, cm-1) are listed. The reactions were carried out in sealed tubes to allow for reaction temperatures above the boiling point of CH2Cl2. Reactions with long reaction times (> 1 h) were protected from light using alumina foil. Dichloromethane was freshly distilled from CaH2 and TfOH (≥99%) was stored under Ar atmosphere. The percentage of active oxidizing agent in mCPBA was determined by iodometric titration.1 All other chemicals were used as received without further purification.

2. Synthesis of Diaryliodonium Salts 3:

2.1 General Procedure for the Synthesis of Electron-Rich Salts:

Ar1-I + Ar2-HmCPBA,

TfOH, CH2Cl2I

Ar1OTf

Ar2

1 2 3 m-Chloroperbenzoic acid (65% active oxidant, 66 mg, 0.25 mmol) and aryl iodide 1 (0.23 mmol) were dissolved in CH2Cl2 (1 mL) in a sealed tube. The arene 2 (0.25 mmol) was added and the solution was cooled to the tabulated temperature followed by dropwise addition of TfOH (40 μL, 0.45 mmol), resulting in a slight heat increase and change of color from a clear to a yellow transparent solution. The solution was stirred at the indicated temperature and time and concentrated in vacuo while still cold. Et2O (1-2 mL) was added and the mixture was stirred at rt for 10 min to precipitate out an off-white solid. The flask was stored in the freezer for 30 min, then the solid was filtered off, washed with cold Et2O and dried under vacuum to give diaryliodonium salt 3. Table S1: Reaction conditions for electron rich arenes. Entry Aryl Iodide Arene T (˚C) Time (min) Product Yield (%)

1 1a 2c 0 10 3c 85 2 1a 2d -78 10 + 10 3d 87 3 1a 2e -78 10 + 10 3e 82 4a 1b 2a 0 45 3c 71

5 1b 2c rt 10 3f 52 6 1c 2a rt 10 3g 85 7 1c 2c rt 10 3h 87

8a 1e 2d 0 15 3k 53 a 3.0 equiv. of TfOH was used.

S2

2.2 General Procedure for Less Reactive Substrates:

Ar1-I + Ar2-HmCPBA,

TfOH, CH2Cl2I

Ar1OTf

Ar2

1 2 3 Performed as described in section 2.1 apart from that mCPBA, 1 and 2 were dissolved in CH2Cl2 (1 mL), TfOH was added dropwise at rt and the mixture was heated to 80 ºC for the time given in Table S2. Table S2: Reaction conditions for less reactive aryl iodides/ arenes. Entry Aryl Iodide Arene Time Product Yield (%)

1a 1a 2a 10 min 3a 85 2 1a 2b 2 h 3b 85 3 1d 2a 14.5 h 3i 85 4a 1e 2a 2 h 3j 60

a 3.0 equiv. of TfOH was used.

2.3 General procedure for direct synthesis of salts 3 from arenes and iodine:

4 Ar-H + I2mCPBA,

TfOH, CH2Cl2I

Ar ArOTf

32 m-Chloroperbenzoic acid (65% active oxidant, 123 mg, 0.47 mmol) and iodine (30.0 mg, 0.12 mmol) were dissolved in CH2Cl2 (1.0 mL) in a sealed tube, which resulted in a dark purple solution that was cooled to 0 ˚C. Arene 2 (4.1-10 equiv, see Table S3) was added followed by dropwise addition of TfOH (41 μL, 0.47 mmol), resulting in a slight heat increase and change of color to a yellow transparent solution. The solution was stirred at the indicated temperature and time (Table S3). Workup and purification was performed as described in section 2.1. Table S3: Reaction conditions for the reaction of arenes with iodine. Entry Arene

(equiv.) T (˚C) Time Product Yield (%)

1 2a (4.1) 80 10 min 3a 78 2 2a (10) rt 22 h 3a 81 3 2c (10) rt 2 h 3h + 3f (3:1) 52 4 2c (4.1) 0 1 h 3h 31 5 2f (10) rt 21 h 3l 57 6 2g (10) rt 19 h 3m 24

S3

3. Analytical data of diaryliodonium salts 3: Diphenyliodonium triflate (3a):2 3

I OTf

Synthesized according to section 2.2, but in 2 ml CH2Cl2, in 85% yield or according to section 2.3 in 81% yield. 3a can also be synthesized according to Table 1; either at rt or at 40 ºC in 89% yield. Analytical data were in agreement with previous reports. (4-Iodophenyl)(phenyl)iodonium triflate (3b):3

I OTf

I Synthesized according to section 2.2 in 85% yield as a white solid. Analytical data were in agreement with previous reports. (4-Methylphenyl)(phenyl)iodonium triflate (3c):4

I OTf

Synthesized according to section 2.1 (Table 1, entry 1) in 85% yield and as an off-white solid. Can also be obtained as described in Table 1, entry 4, using 3 equiv TfOH, in 71% yield. The 13C NMR given in reference 4 is in accordance with our data, whereas the 1H NMR differs. mp: 120-121 ˚C (lit4: 122-125 ˚C); IR (film): 3082, 3060, 2922, 1258, 1170, 1026 cm-1; 1H NMR (400 MHz, DMSO-d6): δ 8.21 (d, J = 7.6 Hz, 2H), 8.12 (d, J = 8.2 Hz, 2H), 7.66 (t, J = 7.6 Hz, 1H), 7.52 (t, J = 7.6 Hz, 2H), 7.34 (d, J = 8.2 Hz, 2H), 2.34 (s, 3H). (4-Methoxyphenyl)(phenyl)iodonium triflate (3d):4

I OTf

OMe Synthesized according to section 2.1, apart from that TfOH was added at rt and the reaction was stirred for 10 min at rt before cooling to -78 ºC and slow addition of arene 2d (0.25 mmol) in CH2Cl2 (1 mL). The reaction was then stirred at -78 ºC for 10 min, delivering 3d in 87% yield as an off-white solid. Analytical data were in agreement with previous reports. (2-Thienyl)(phenyl)iodonium triflate (3e):5

I OTfS

Synthesized according to section 2.1 apart from that TfOH was added at rt and the reaction was stirred for 10 min at rt before cooling to -78 ºC and slow addition of arene 2e (0.25 mmol) in CH2Cl2 (1 mL). The reaction was then stirred at -78 ºC for 10 min, giving 3e in 82% yield as a grey solid. Analytical data were in agreement with previous reports.

S4

Bis(4-methylphenyl)iodonium triflate (3f):6

I OTf

Synthesized according to section 2.1 in 52% yield as an off-white solid. The 13C NMR given in reference 6 is in accordance with our data, whereas the 1H NMR differs. 1H NMR (400 MHz, DMSO-d6): δ 8.08 (d, J = 8.0 Hz, 4H), 7.32 (d, J = 8.0 Hz, 4H), 2.34 (s, 6H); 13C NMR (100 MHz, DMSO-d6): δ 142.5, 135.0, 132.3, 120.7 (q, J = 320 Hz, CF3SO3

–), 113.0, 20.8; HRMS (ESI): calcd for C14H14I ([M – TfO–]+): 309.0135; found 309.0131. (2-Methylphenyl)(phenyl)iodonium triflate (3g):7

I OTf

Synthesized according to section 2.1 to give 3g in 85% yield as an off-white solid. Analytical data have not been given in previous reports. 1H NMR (400 MHz, DMSO-d6): δ 8.39 (d, J = 7.8 Hz, 1H), 8.20 (d, J = 7.7 Hz, 2H), 7.66 (t, J = 7.4 Hz, 1H), 7.57 (m, 2H),7.51 (t, J = 7.7 Hz, 2H), 7.32 (t, J = 6.2 Hz, 1H), 2.61 (s, 3H); 13C NMR (100 MHz, DMSO-d6): 140.6, 137.1, 135.0, 132.9, 132.0, 131.8, 131.4, 129.3, 121.4, 120.7 (q, J = 320 Hz, CF3SO3

–), 115.9, 25.0; HRMS (ESI): calcd for C13H12I ([M – TfO–]+): 294.9978; found 294.9985. 2-Methylphenyl(4-methylphenyl)iodonium triflate (3h):8

I OTf

Synthesized according to section 2.1 in 87% yield as an off-white solid. Also synthesized as described in section 2.3 as a regioisomeric mixture with 3f (ratio 3h:3f 3:1) in 52% combined yield or as the single regioisomer in 31% yield. Analytical data were in agreement with previous reports. 1H NMR (400 MHz, DMSO-d6): δ 8.36 (d, J = 8.6 Hz, 1H), 7.32 (d, J = 8.6 Hz, 2H), 7.57 (m, 2H), 7.32 (m, 3H) 2.60 (s, 3H), 2.33 (s, 3H); 13C NMR (100 MHz, DMSO-d6): δ 142.5, 140.5, 137.0, 135.0, 132.8, 132.4, 131.4, 129.3, 121.5, 120.7 (q, J = 321 Hz, CF3SO3

–), 112.2, 25.0, 20.8; HRMS (ESI): calcd for C14H14I ([M – TfO–]+): 309.0135; found 309.0140. (4-Nitrophenyl)(phenyl)iodonium triflate (3i):3

I OTf

O2N Synthesized according to section 2.2 in 85% yield as a white solid. Analytical data were in agreement with previous reports.

S5

(6-Chloro-pyridin-3-yl)(phenyl)iodonium triflate (3j):9

N

I OTf

Cl Synthesized according to section 2.2, apart from that 3 equiv TfOH was used, delivering 3j in 60% yield as a white solid. Analytical data have not been given in previous reports. m.p.: 153-155 ˚C; 1H NMR (400 MHz, DMSO-d6): δ 9.17 (d, J = 2.3 Hz, 1H), 8.70 (dd, J = 8.5, 2.3 Hz, 1H), 8.28 (d, J = 7.6 Hz, 2H), 7.75 (d, J = 8.5 Hz, 1H), 7.70 (t, J = 7.6 Hz, 1H), 7.56 (t, J = 7.6 Hz, 2H); 13C NMR (100 MHz, DMSO-d6): δ 154.3, 153.4, 145.5, 135.2, 132.4, 132.0, 127.6, 120.7 (q, J = 322 Hz, CF3SO3

–), 116.9, 114.2; IR (film): 3084, 3055, 1554, 1445, 1260, 1172, 1027 cm-1; HRMS (ESI): calcd for C11H8ClIN ([M – TfO–]+): 315.9384; found 315.9393. (6-chloro-pyridin-3-yl)(4-methoxyphenyl)iodonium triflate (3k):

N

I OTf

Cl OMe Synthesized according to section 2.1, apart from that TfOH (3 equiv) was added at rt and the reaction was stirred for 10 min at rt before cooling to -78 ºC and slow addition of arene 2d (0.25 mmol) in CH2Cl2 (1 mL). The reaction was then stirred at -78 ºC for 10 min, delivering 3k in 53% yield as a slightly grey solid. m.p.: 101-103 ˚C; 1H NMR (400 MHz, DMSO-d6): δ 9.12 (d, J = 2.1 Hz, 1H), 8.64 (dd, J = 8.5, 2.1 Hz, 1H), 8.20 (d, J = 8.9 Hz, 2H), 7.72 (d, J = 8.5 Hz, 1H), 7.10 (d, J = 8.9 Hz, 2H) 3.80 (s, 3H); 13C NMR (100 MHz, DMSO-d6): δ 162.2, 154.0, 153.2, 145.3, 137.3, 127.5, 120.7 (q, J = 321 Hz, CF3SO3

–), 117.7, 114.6, 105.7, 55.8; IR (film): 3090, 3047, 1572, 1443, 1258, 1172, 1026 cm-1; HRMS (ESI): calcd for C12H10ClINO ([M – TfO–

]+): 345.9490; found 345.9501. Bis(4-chlorophenyl)iodonium triflate (3l):

I OTf

ClCl Synthesized according to section 2.3 in 57% yield as a single regioisomer. m.p.: 181-183 ˚C; 1H NMR (400 MHz, DMSO-d6): δ 8.26 (d, J = 8.6 Hz, 4H), 7.63 (d, J = 8.6 Hz, 4H); 13C NMR (100 MHz, CDCl3): δ 139.8, 136.8, 132.5, 120.0 (q, J = 318 Hz, CF3SO3

–), 111.2; IR (film): 3086, 1260, 1172, 1026 cm-1; HRMS (ESI): calcd for C12H8Cl2I ([M – TfO–]+): 348.9042; found 348.9041. Bis(2,4-dimethyl-5-nitrophenyl)iodonium triflate (3m):

OTfI

O2N NO2 Synthesized according to section 2.3 in 24% yield as a single regioisomer. m.p.: 200-202 ˚C; 1H NMR (400 MHz, DMSO-d6): δ 9.10 (s, 2H), 7.70 (s, 2H), 2.65 (s, 6H), 2.53 (s, 6H); 13C NMR (100 MHz, DMSO-d6): δ 147.5, 146.4, 137.9, 135.1, 132.9, 120.7 (q, J = 320 Hz, CF3SO3

–), 117.4, 24.7, 19.6; IR (film): 3095, 1523, 1342, 1261, 1173, 1024 cm-1; HRMS (ESI): calcd for C16H16IN2O4 ([M – TfO–]+): 427.0149; found 427.0145.

S6

References 1 A. I. Vogel, B. S. Furniss, A. J. Hannaford, V. Rogers, P. W. G. Smith and A.

R. Tatchell, Vogel's Textbook of Practical Organic Chemistry, 1978. 2 Commercially available. 3 M. D. Hossain and T. Kitamura, Tetrahedron, 2006, 62, 6955-6960. 4 T. Kitamura, J. Matsuyuki, K. Nagata, R. Furuki and H. Taniguchi, Synthesis,

1992, 945-946. 5 D. Bykowski, R. McDonald, R. J. Hinkle and R. R. Tykwinski, J. Org. Chem.,

2002, 67, 2798-2804. 6 J. L. Dektar and N. P. Hacker, J. Org. Chem., 1990, 55, 639-647. 7 M. A. Carroll, V. W. Pike and D. A. Widdowson, Tetrahedron Lett., 2000, 41,

5393-5396. 8 A. Shah, V. W. Pike and D. A. Widdowson, J. Chem. Soc., Perkin Trans. 1,

1997, 2463-2465. 9 V. K. Aggarwal and B. Olofsson, Angew. Chem. Int. Ed., 2005, 44, 5516-

5519; B. Olofsson and V. K. Aggarwal, Proc. 2nd Int. Conf. on Hypervalent Iodine, 2006, 47-50.

4. NMR spectra of diaryliodonium salts 3: 1H NMR-spectra for compounds 3a-m and 13C NMR-spectra for compounds 3g,h,j-m follow on the coming pages.

S7

98

76

54

32

10

ppm

7.3

7.4

7.5

7.6

7.7

7.8

7.9

8.0

8.1

8.2

8.3

8.4

8.5

ppm

7.514

7.518

7.533

7.550

7.553

7.651

7.653

7.669

7.686

7.688

8.235

8.238

8.256

8.258

4.007

2.000

3.952

OI SO

O

CF3

3a

400 MHz

DMSO

9.0 8.5 8.0 7.5 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 ppm

7.07.27.47.67.88.08.28.48.68.89.0 ppm

7.535

7.553

7.657

7.674

7.690

7.889

7.909

7.982

8.002

8.229

8.247

1.943

1.058

3.947

2.000

O

I

SO O

CF3

I

3b

400 MHzDMSO

98

76

54

32

1ppm

7.3

7.4

7.5

7.6

7.7

7.8

7.9

8.0

8.1

8.2

8.3

8.4

8.5

ppm

7.328

7.348

7.501

7.520

7.540

7.638

7.656

7.675

8.111

8.132

8.201

8.220

2.044

2.041

1.014

1.939

1.936

OI SO

O

CF3

3c

400 MHz

DMSO

2.4

2.6

ppm

2.3393.000

98

76

54

32

1ppm

6.6

6.8

7.0

7.2

7.4

7.6

7.8

8.0

8.2

8.4

ppm

6.915

6.937

7.386

7.406

7.425

7.532

7.550

7.569

7.934

7.951

7.956

7.970

2.006

2.061

1.037

4.050400 MHz

DMSO

OI SO

O

CF3

OMe

3d

3.5

4.0

ppm

3.8013.000

-0.59.0 8.5 8.0 7.5 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 ppm

6.97.07.17.27.37.47.57.67.77.87.98.08.18.28.3 ppm

7.129

7.139

7.149

7.152

7.260

7.436

7.455

7.475

7.575

7.595

7.612

7.692

7.705

7.880

7.883

7.890

7.960

7.980

0.972

2.083

1.026

0.975

0.944

2.001

O

I

SO O

CF3

S

3e

400 MHzCDCl3

-2-116 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 ppm

2.32.42.52.6 ppm

2.336

6.010

7.07.27.47.67.88.08.28.4 ppm

7.313

7.333

8.075

8.095

4.000

3.957

O

I

SO O

CF3

3f

400 MHzDMSO

8.5 8.0 7.5 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 ppm

7.07.27.47.67.88.08.28.48.68.8 ppm

7.316

7.331

7.500

7.518

7.537

7.570

7.586

7.637

7.655

7.674

8.192

8.212

8.382

8.402

0.976

3.964

1.067

1.811

1.000

2.62.8 ppm

2.614

3.510

O

I

SO O

CF3

3g

400 MHzDMSO

200

180

160

140

120

100

80

60

40

20

0ppm

24.988

115.859

119.157

121.417

122.333

129.294

131.434

131.807

131.975

132.859

135.037

137.070

140.578

OI SO

O

CF3

3g

100 MHz

DMSO

OI SO

O

CF3

3h

400 MHz

DMSO

98

76

54

32

10

ppm

6.5

7.0

7.5

8.0

8.5

9.0

ppm

7.311

7.330

7.555

7.572

8.071

8.090

8.352

8.372

3.098

2.210

2.000

0.895

2.4

2.6

2.8

ppm

2.330

2.604

3.047

3.073

200

180

160

140

120

100

80

60

40

20

0ppm

20.821

24.969

112.213

121.536

129.269

131.396

132.432

132.787

135.039

136.967

140.473

142.514

OI SO

O

CF3

3h

100 MHz

DMSO

9.0 8.5 8.0 7.5 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 ppm

7.47.57.67.77.87.98.08.18.28.38.48.58.68.7 ppm

7.557

7.575

7.593

7.596

7.720

7.740

7.757

8.242

8.261

8.309

8.330

8.331

8.405

8.423

8.425

1.970

1.002

1.885

2.063

2.000

O

I

SO O

CF3

O2N

3i

400 MHzMeOD

10.0 9.5 9.0 8.5 8.0 7.5 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 ppm

7.27.47.67.88.08.28.48.68.89.09.29.49.69.8 ppm

7.540

7.545

7.560

7.579

7.678

7.696

7.715

7.735

7.756

8.271

8.273

8.292

8.294

8.687

8.693

8.709

8.715

9.169

9.175

2.039

1.038

1.022

2.000

1.004

0.983

O

I

N

S OO

CF3

Cl

3j

400 MHzDMSO

-10

210

200

190

180

170

160

150

140

130

120

110

100

90

80

70

60

50

40

30

20

10

0ppm

38.894

39.103

39.311

39.520

39.728

39.937

40.146

114.156

115.870

116.917

119.073

122.279

125.480

127.640

131.954

132.369

135.241

145.543

153.367

154.288

OI

N

SO

O

CF3

Cl

3j

100 MHz

DMSO

10

98

76

54

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1ppm

6.5

7.0

7.5

8.0

8.5

9.0

9.5

10.0

ppm

7.085

7.108

7.717

7.738

8.188

8.210

8.626

8.631

8.647

8.653

9.120

9.125

1.959

0.964

1.903

0.965

0.919

4.0

ppm

3.8013.000

OI

N

SO

O

CF3

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OMe

3k

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DMSO

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6.87.07.27.47.67.88.08.28.48.68.89.09.2 ppm

7.623

7.645

8.249

8.270

4.000

3.992

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CF3

ClCl

3l

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