Table 1. Optimization of the Reaction Conditions^a.

entry	cat.	oxidant	solventb	T (°C)	yield (%)c
1d	[RhCp*Cl2]2	Cu(OAc)2·H2O Na2CO3	m-xyl	150	SM
2d	[RhCp*Cl2]2	AgOAc	m-xyl	150	SM
3d	[RhCp*Cl2]2	AgOAc	tol	100	SM
4	Pd(OAc)2	Cu(OAc)2	MeCN	105	20
5	Pd(OAc)2	O2/NaOAc	DMF	120	20
6	Pd(OAc)2	BQ/AcOH	DMF	120	33
7	Pd(OAc)2	Cu(OAc)2	DMF	120	50
8	Pd(OAc)2	AgOAc	DMF	120	64
9	Pd(OAc)2	AgOAc + PivOH (1 equiv)	DMF	120	75
10	Pd(OAc)2	AgOAc + PivOH (5 equiv)	DMF	120	88 (80)e
11f	Pd(OAc)2	AgOAc + PivOH (5 equiv)	DMF	120	68

^aTypical conditions: 1a (0.2 mmol, 1 equiv), 2a (0.3 mmol, 1.5 equiv), catalyst (10 mol %), oxidant (2.1 equiv), solvent (2.0 mL), air atmosphere, unless otherwise stated.

^bm-xyl, m-xylene; tol, toluene.

^cDetermined by ¹H NMR analysis vs 1,3,5-trimethoxybenzene. The number in parentheses is the isolated yield.

^d[RhCp*Cl₂]₂ (2.5 mol %).

^eAt 90 °C, 3aa was isolated in 73% yield.

^f1a (3 mmol), Pd(OAc)₂ (5 mol %).