Table 2.

Chlorination of 2,4-dimethyliodobenzene (9a).

			Distributionb (%)
Entry	Methoda	Time (h)	9a : 9bc : 10 : 11
1	A	0.5	83 : 17 : / : /
2	A	2	54 : 46 : trace : trace
3	A	20	33 : / : 30 : 37
4	B	20	/ : / : 47 : 53
5	D	6	19 : 22 : 28 : 31

Reaction conditions: 9a (1.0 mmol), ambient temperature. ^a Method A: conc. HCl (2.0 mmol), 30% aq. H₂O₂ (1.0 mmol), TFE (1.0 mL); Method B: conc. HCl (4.0 mmol), 30% aq. H₂O₂ (2.0 mmol), TFE (1.0 mL); Method C: conc. HCl (4.0 mmol), 30% aq. H₂O₂ (4.0 mmol), TFE (1.0 mL). Method D: Cl₂, hexane (10 mL). ^b Distribution of products determined by ¹H-NMR spectroscopy. ^c 9b was determined by its characteristic signals for ArICl₂ compounds in ¹H-NMR spectra of the reaction mixture – 8.07 ppm (d, J = 8 Hz, 1H).