Optimization of reaction conditions^a.

Entry	Catalyst	Oxident (R)	Yieldb (%)
			4a	4aa	4ab
1	PPh3AuNTf2	3a (2,6-Br2)	<1	90	<1
2	IPrAuNTf2	3a (2,6-Br2)	17	72	<1
3	Zn(OTf)2	3a (2,6-Br2)	75	<1	12
4	Fe(OTf)3	3a (2,6-Br2)	65	<1	32
5	Yb(OTf)3	3a (2,6-Br2)	69	<1	12
6	In(OTf)3	3a (2,6-Br2)	64	<1	18
7	Sm(OTf)3	3a (2,6-Br2)	74	<1	<1
8	Sc(OTf) 3	3a(2,6-Br2)	95	<1	<1
9	HNTf2	3a (2,6-Br2)	39	<1	23
10	MsOH	3a (2,6-Br2)	<1	<1	70
11	Sc(OTf)3	3b (2,6-Cl2)	88	<1	6
12	Sc(OTf)3	3c (2-Br)	80	<1	11

^aReactions run in vials; [1a] = 0.05 M.

^bEstimated by ¹H NMR using diethyl phthalate as an internal reference.