Entry

Reagents used

Yield

Reaction time

Reaction steps

Remarks

Ref.

1

PTC/M2CO3/CH2Cl2, M = K, Na

45% - 70%

1 - 4 hrs

3

VOC used

[22]

2

BF3-SiO2

78% - 88%

1 - 2 mins

2

Solvent free

[28]

3

Mineral acid, NaOH, CH3COONa

80%

3.5 hrs

3

VOC used

[31]

4

alkali

54% - 75%

-

3

Temp and pH control

[6]

5

Amberlite IR120 (Na+), acid, cyclohexane

65% - 74%

1 - 2 hrs

3

VOC used

[30]