Phenol oxidation with hypervalent iodine reagents

(1)The mechanism of phenol oxidation with hypervalent iodine reagents begins with the formation of an aryloxyiodonium(III) intermediate.

(2)When the phenol contains an electron-withdrawing group in the para position and at least one ortho hydrogen, stable iodonium ylides result.

Iodonium ylides undergo cycloaddition reactions with unsaturated functional groups, and react with nucleophiles and electrophiles to give substitution products.

(3)Oxidative coupling of bis(phenols) takes place in the presence of iodine(III) reagents.

[15] (13)The organic oxidant 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) can accomplish many of the same transformations that iodine(III) reagents can, sometimes with higher selectivity.

[16] Organohypervalent iodine reagents are typically solids that are fairly stable at room temperature and generally insensitive to atmospheric oxygen and moisture.

Iodosobenzene can be prepared by hydrolysis of either (dichloroiodo)benzene or IBD and should be stored in a refrigerator in dark containers.

The mixture was stirred at room temperature for 10 minutes, diluted with water, and extracted with diethyl ether (3 × 10 mL).

The combined organic extracts were washed with saturated aqueous sodium chloride solution, dried (MgSO4), and concentrated in vacuo.