Selected optimization details for the trifluoromethylarylation.

Entry	Deviation from optimized conditions	Isolated yield, 4a (%)
1	None	72%
2	HFIP (0.2 M) at 40 °C	67%
3	HFIP (0.2 M) at rt	58%
4	HFIP (0.2 M) at 80 °C	53%
5	instead of 3	34%
6	instead of 3	nr
7	and CF3SO2Na instead of 3	nr
8	CH2Cl2, CH3CN or AcOH (0.2 M) at rt	nr
9	TFE (0.2 M) at rt	11%
10	2.0 equiv. of 1a	65%
11	2.0 equiv. of 2a	63%
12	2.0 equiv. of 3	22%