Table 1.

In Situ Halogenation

reagent
entry	arene	base	product	yield
1		CCl4 tBuOLi		80%
2		CBr4 K3Po4		82%
3		(BrCF2)2 tBuOLi		77%
4		(BrCF2)2 tBuOLi		65%
5		(BrCF2)2 tBuOLi		80%
6		CBr4 tBuOLi		56%
7b		CBr4 tBuOLi		30%
8	C6Cl5H	ICl tBuOLi		90%
9		CBr4 tBuOLi		55%
10		CBr4 tBuOLi		40%
11	C6F5H	I2 K3Po4		85%
12		I2 tBuOLi		95%
13c		ICl tBuOLi		58%
14d		ICl tBuOLi		32%
15		I2 tBuOLi		97%

^aSubstrate (1 equiv), base (2.0–4.0 equiv), halogenating reagent (1.0–3.0 equiv). Yields are isolated yields. See the Supporting Information for details.

^bm-Xylene solvent.

^c1,3,5-Trifluorobenzene (3 equiv), ICl (1 equiv).

^d1,3,5-Trifluorobenzene (1 equiv), ICl (3 equiv).