The ultrasound-assisted oxysulfonylation of different alkenes using sodium salts of organosulfinic acids under air atmosphere is described. The reaction is chemo- and regioselective and the corresponding β-keto-sulfones were obtained in good yields as major products. The use of ultrasound greatly accelerated the formation of products when compared to the conventional methods.
Keywords:
ultrasound; oxysulfonylation; iron trichloride; β-keto-sulfones
| entry | Solvent | time / h | 3ab b determined by gas chromatography (GC) analysis; / % | 4ab b determined by gas chromatography (GC) analysis; / % |
|---|---|---|---|---|
| 1 | CH2Cl2 | 24 | 39 | 30 |
| 2 | H2O | 24 | 20 | 6 |
| 3 | THF | 24 | 5 | - |
| 4 | acetone | 24 | 67 | 18 |
| 5 | MeCN | 24 | 53 | 27 |
| 6c c the reaction was performed under sonication; | acetone | 1 | 61 | 20 |
| 7c c the reaction was performed under sonication; | MeCN | 1 | 75 | 4 |
| 8c c the reaction was performed under sonication; | MeCN:H2Od d a 2:1 mixture was used. | 1 | 82 | 6 |
| entry | FeCl3 / mol% | 3ab b determined by gas chromatography (GC) analysis. / % | 4ab b determined by gas chromatography (GC) analysis. / % |
|---|---|---|---|
| 1 | - | - | - |
| 2 | 5 | 19 | 50 |
| 3 | 10 | 34 | 59 |
| 4 | 20 | 75 | 4 |
| 5 | 30 | 70 | 24 |
| 6 | 40 | 52 | 35 |
| entry | FeCl3 / mol% | (NH4)2S2O8 / mol% | 3ab b determined by gas chromatography (GC) analysis; / % | 4ab b determined by gas chromatography (GC) analysis; / % | 5b b determined by gas chromatography (GC) analysis; / % |
|---|---|---|---|---|---|
| 1 | 20 | - | 75 | 9 | - |
| 2 | - | 20 | 39 | 2 | - |
| 3 | 20 | 20 | 91 | 4 | - |
| 4 | 20 | 40 | 84 | 3 | 9 |
| 5 | 100 | 100 | 6 | 51 | 22 |
| 6c c the reaction was performed under stirring for 24 h. | 20 | 20 | 80 | 10 | - |
| entry | 1 | 2 | 3 | 4 | 3a a Isolated yield; / % | 3:4b b determined by gas chromatography (GC) analysis; |
|---|---|---|---|---|---|---|
| 1 | PhSO2Na 2a |
82 | 96:4 | |||
| 2 | 2a | 63c c the reaction was sonicated for 2 h; | 71:29 | |||
| 3 | 2a | 90 | 0:100 | |||
| 4 | 2a | -d d a complex mixture of products was obtained; | - | |||
| 5 | 2a | 67 | 95:5 | |||
| 6 | 2a | 52 | 67:33 | |||
| 7 | 2a | 89e e the yield refers to the mixture of compounds 3g and 4g; | 10:90 | |||
| 8 | 2a | -d d a complex mixture of products was obtained; | - | |||
| 9 | 2a | -f f the corresponding phosphinoxide was obtained as product; | - | |||
| 10 | 2a | - | - | |||
| 11 | 2a | -g g the corresponding boronic acid 1j was obtained as product. | - | |||
| 12 | PhSO2Na 2a |
- | - | |||
| 13 | 1a |
p-TolSO2Na 2b |
70 | 90:10 | ||
| 14 | 1a | MeSO2Na 2c |
40 | 96:4 | ||
| 15 | 1a | - | - | |||
| entry | Condition | 3ab b determined by gas chromatography (GC) analysis. TEMPO: (2,2,6,6-tetramethylpiperidin-1-yl)oxyl. /% | 6b b determined by gas chromatography (GC) analysis. TEMPO: (2,2,6,6-tetramethylpiperidin-1-yl)oxyl. /% |
|---|---|---|---|
| 1 | MeCN, 25 ºC, 1 h, ))), Ar | 19 | 14 |
| 2 | MeCN, TEMPO, 25 ºC, 1 h, ))), Ar | - | - |
