Table 1 Screening of reaction conditions.^a


Entry	Variation from ‘standard conditions’	Yield (%)^b
1	None	80 (61)^c
2	w/o FeBr₂	trace
3	FeCl₂ instead of FeBr₂	71
4	Fe(OTf)₂ instead of FeBr₂	75
5	Fe(OAc)₂ instead of FeBr₂	32
6	Fe(acac)₃ instead of FeBr₂	10
7	Cu(OTf)₂ instead of FeBr₂	<10
8	[[CH₃(CH₂)₆CO₂]₂Rh]₂ instead of FeBr₂	34
9	TMOPP-Co instead of FeBr₂	trace
10	Ru₃(CO)₁₃ instead of FeBr₂	<10
11	w/o Cy₃PO	70
12	In toluene	75
13	In THF	70
14	10 mol% FeBr₂ and 15 mol% Cy₃PO instead	61

^aUnless otherwise specified, all reactions were carried out using 1a (0.1 mmol), NBS (0.18 mmol), N(nBu₄)N₃ (0.3 mmol), (PhO)₂POOH (0.075 mmol), FeBr₂ (0.015 mmol), and Cy₃PO (0.02 mmol) in PhCl (1.0 mL) at 100 °C for 36 h.
^bIsolated yields after chromatography.
^cScale-up reaction by using 1.0 mmol of 1a.

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