S1 Tracking Gold Acetylides in Gold(I)-Catalyzed Cycloisomerization Reactions of Enynes Antoine Simonneau, a Florian Jaroschik, a Denis Lesage, a Magdalena Karanik, a Régis Guillot, b Max Malacria, a Jean-Claude Tabet, a Jean-Philippe Goddard, a Louis Fensterbank,* a Vincent Gandon,* b Yves Gimbert* c a Institut Parisien de Chimie Moléculaire (UMR CNRS 7201) - FR 2769 UPMC univ Paris 06, C. 229, 4 place Jussieu, 75005 Paris, France. Fax: 33 (0)1 44 27 73 60; Tel: 33 (0)1 44 27 70 68; E-mail: louis.fensterbank@upmc.fr b ICMMO (UMR CNRS 8182), Université Paris-Sud 11, 91405 Orsay cedex, France. Fax: 33 (0)1 69 15 47 47; Tel: 33 (0)1 69 15 39 31; E-mail: vincent.gandon@u-psud.fr c DCM (UMR CNRS 5250), ICMG-FR 2607 BP 53 38041 Grenoble cedex 9, France. Fax: 33 (0)4 76 51 44 94; Tel: 33 (0)4 76 51 44 26; E-mail: yves.gimbert@ujf-grenoble.fr Table of Contents 1. General Methods S1 2. Procedure for the synthesis of gold acetylides S2 3. Preparation of the digold complexes S3 4. Preparation of the trigold complex S5 5. Organic products S5 6. NMR Spectra S7 7. NMR Monitoring Corresponding to Scheme 5 S26 8. Mass Spectrometry S40 9. Computations S47 General Methods. THF was distilled over sodium-benzophenone ketyl. Dichloromethane, was distilled over calcium hydride. n-Butyllithium was purchased as 2.5 M solution in hexane. Other reagents were commercially available and used without further purification. Thin layer chromatography (TLC) was performed on Merck 60 F 254 silica gel. Merck Gerudan SI 60 Å silica gel (0.035-0.070 mm) was used for column chromatography. NMR spectra ( 1 H, 13 C, 31 P, DEPT, COSY, HMQC, HMBC, NOE) were recorded at room temperature on a Bruker AVANCE spectrometer (400 MHz). Chemical shifts are given in ppm, referenced to the residual proton resonance of the solvents (! = 7.26 for CHCl 3 ), to the residual carbon resonance of the solvent (! = 77.16 for CDCl 3 ), or to the phosphorus Electronic Supplementary Material (ESI) for Chemical Science This journal is © The Royal Society of Chemistry 2011