Table 1.

Optimization of the Reaction Conditions^a

entry	Rh(III)	additive	yield (%)d
1	[Cp*RhCl2]2	AgOAcb	<12c
2	A1	none	55
3	A1	p-TsOHb	72
4	A1	CsOAc	81
5	A2	CsOAc	91
6	A3	CsOAc	99
7	A4	CsOAc	92
8	B3	CsOAc	99
9e	B3	CsOAc	99

^aReaction Conditions: 1a (1.0 equiv), 2a (1.2 equiv), additive (2.0 equiv), Rh(III) catalyst (5 mol %) in HFIP (0.3 M), at 60 °C for 16 h.

^b10 mol % of additive was used.

^cDetermined by ¹H NMR.

^dYield of isolated product.

^eCatalyst loading was decreased to 2 mol %, reaction temperature was decreased to 50 °C.