Table 1 Development of the Reactiona

From: Dearomative di- and trifunctionalization of aryl sulfoxides via [5,5]-rearrangement

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Entry

Base

T1, t1

T2, t2

Yieldb

1

DABCO

−50 °C, 18 h

−70 °C, 12 h

Trace

2

DIPEA

−50 °C, 18 h

−70 °C, 12 h

40

3

NEt3

−50 °C, 18 h

−70 °C, 12 h

63

4

DBU

−50 °C, 18 h

−70 °C, 12 h

38

5

4-ethylmorpholine

−50 °C, 18 h

−70 °C, 12 h

70

6

2-methylpyridine

−50 °C, 18 h

−70 °C, 12 h

34

7

4-ethylmorpholine

−50 °C, 12 h

−70 °C, 12 h

50

8

4-ethylmorpholine

−40 °C, 18 h

−70 °C, 12 h

30

9

4-ethylmorpholine

−55 °C, 18 h

−70 °C, 12 h

79

10

4-ethylmorpholine

−60 °C, 18 h

−70 °C, 12 h

66

11

4-ethylmorpholine

−55 °C, 18 h

−95 °C, 12 h

53

12

4-ethylmorpholine

−55 °C, 18 h

−80 °C, 12 h

71

13

4-ethylmorpholine

−55 °C, 18 h

−60 °C, 12 h

54

14

4-ethylmorpholine

−55 °C, 18 h

−70 °C, 6 h

72

15

4-ethylmorpholine

−55 °C, 18 h

−70 °C, 12 h

81(73)c

  1. aReactions were performed in a one-pot three-step manner: (1) 1a (0.5 mmol), 2a (3.0 equiv), Tf2O (1.5 equiv), T1 (°C), t1 (h); (2) base (2.5 equiv), −95 °C, 30 min; (3) 3a (2.0 equiv), −95 °C to T2 (°C), t2 (h). Tf2O was added at −78 °C. Tf2O: triflic anhydride. DABCO: triethylenediamine. DIPEA: diisopropyl triethylamine. DBU: 1,8-diazabicyclo[5.4.0]undec-7-ene.
  2. bNMR yields using mesitylene as internal standard and isolated yields given in parentheses.
  3. cBase and Nu were added in one portion. Ortho-alkylated product 5 was obtained in 6% yield.
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