Table 1.

Selected optimization studies

Entry	Catalyst	Ligand/Additive	Solvent	Temp. (°C)	Yield (%)*
1	5 mol% [Rh(nbd)dppp]PF6	10 mol% BHT	Xylenes	130	0
2	10 mol% [Rh(COD)Cl]2		Toluene	130	<5
3	10 mol% [Rh(COD)Cl]2		CIPh	150	23(34)
4	10 mol% [Rh(COD)Cl]2		Xylenes	150	27(30)
5	10 mol% [Rh(COD)Cl]2		1,4-Dioxane	150	43(51)
6	10 mol% [Rh(COD)Cl]2	20 mol% COD	1,4-Dioxane	150	47(57)
7	10 mol% [Rh(COD)Cl]2	20 mol% P(C6F5)3	1,4-Dioxane	150	58(65)
8	10 mol% [Rh(COD)Cl]2	10 mol% P(3,5-C6H3(CF3)2)3	1,4-Dioxane	150	67(74)
9	10 mol% [Rh(COD)Cl]2	22 mol% P(3,5-C6H3(CF3)2)3	1,4-Dioxane	150	82
10	10 mol% [Rh(COD)Cl]2†	22 mol% P(3,5-C6H3(CF3)2)3	1,4-Dioxane	150	76(88)
11	5 mol% [Rh(C2H4)2Cl]2	24 mol% P(3,5-C6H3(CF3)2)3§	1,4-Dioxane	150	87
12	5 mol% [Rh(C2H4)2Cl]2‡	24 mol% P(3,5-C6H3(CF3)2)3§	1,4-Dioxane	150	0‖

^*Isolated yield; numbers in parentheses are brsm yield.

^†20 mol% 3 was used with 71 h reaction time.

^‡no 3 was added.

^§The reaction time was 48 h.

^‖Decarbonylation products were observed as an inseperable mixture.