Table 3.

Conditions of Au catalyzed thioether addition to thioalkyne.^[a]

Alternation from above conditions	Convn. of 1a [%][b]	Yield 7a [%]
none	>95	75
5% Cu(OTf)2 instead of [Au]	>95	39
5% AgOTf instead of [Au]	>95	49
[Au]=IPrAuNTf2	>95	60
8b, 8c, 8d	<5	<5
Other catalysts: Pd, Ir, Ru, Rh, Pt, HOTf	<20	<5

^[a]Reaction conditions: 5 mol% catalyst was added to a DCE solution (0.6 mL) of thioalkyne (0.1 mmol) and thioether (1.2 equiv), and reaction was kept at 608C for 6 h.

^[b]Conversion and yield were determined by ¹H NMR spectroscopy using dimethylsulfone as internal standard.