Table 2.

Screening catalysts and solvents.

entrya	gold catalyst/silver salt	solvent	trans/cisb	yield (%)b
1	(t-Bu)2(o-biphenyl)PAuCl/AgOTf	toluene	5.3:1	67
2	(t-Bu)2(o-biphenyl)PAuCl/AgSbF6	toluene	2.2:1	35
3	(t-Bu)2(o-biphenyl)PAuCl/AgPF6	toluene	2.6:1	62
4	(t-Bu)2(o-biphenyl)PAuCl /AgBF4	toluene	–	<5
5	(t-Bu)2(o-biphenyl)PAuCl/AgClO4	toluene	4.1:1	76
6	Ph3PAuCl/AgClO4	toluene	–	<5
7	Cy3PAuCl/AgClO4	toluene	–	<5
8	IPrAuCl/AgClO4c	toluene	4.4:1	63
9	L1AuCl/AgClO4d	toluene	3.1:1	50
10	(t-Bu)2(o-biphenyl)PAuCl/AgClO4	dioxane	4.0:1	63
11	(t-Bu)2(o-biphenyl)PAuCl/AgClO4	CH3NO2	2.8:1	47
12e	(t-Bu)2(o-biphenyl)PAuCl/AgClO4	DCE	1.8:1	34
13e	(t-Bu)2(o-biphenyl)PAuCl/AgClO4	THF	1.8:1	76
14e	(t-Bu)2(o-biphenyl)PAuCl/AgClO4	benzene	3.2:1	60
15e	(t-Bu)2(o-biphenyl)PAuCl/AgClO4	CH3CN	–	<5

^aReactions were carried out in toluene (0.5 mL) at 0.25 mmol scale, 1a (0.25 mmol) and 2a (0.375 mmol) were added in one portion. ^bYield and selectivity were determined by ¹H NMR spectroscopy (internal standard: trimethyl(phenyl)silane). ^cIPr= N,N’-bis(2,6-diisopropylphenyl)imidazol-2-ylidene. ^dL¹ = (Cy)₂(2',4',6'-triisopropyl-o-biphenyl)P. ^eReactions were carried out under reflux.