Table 1. Selected optimization studies ^a .

Entry	Ligand (12 mol%)	Solvent	Bite angle b (°)	Yield c
1	dppf	Xylenes	96	24% (34%)
2	dppm	Xylenes	72	<5%
3	dppe	Xylenes	85	<5%
4	dppp	Xylenes	91	13%
5	dppb	Xylenes	98	29%
6	DPEphos	Xylenes	104	11%
7	t-BuXphos	Xylenes	—	43%
8	Xantphos	Xylenes	111	85%
9	Xantphos	m-Xylene	111	63% (71%)
10	Xantphos	o-Xylene	111	29% (35%)
11	Xantphos	p-Xylene	111	62%
12	Xantphos	Ethylbenzene	111	91%

^aConditions: ynone 1a (0.20 mmol), [Rh] : ligand = 1 : 1.2, solvent (0.1 M).

^bSee ref. 12 for bite-angle values.

^cIsolated yields; number in parenthesis is percent conversion of starting material.