Gold Catalysis: Catalyst Oxidation State Dependent Dichotomy in the Cyclization of Furan–Yne Systems with Aromatic Tethers. Issue 1 (13th November 2012)

• Record Type: Journal Article
• Authors: Hashmi, A. Stephen K.; Hofmann, Julia; Shi, Shuai; Schütz, Alexander; Rudolph, Matthias; Lothschütz, Christian; Wieteck, Marcel; Bührle, Miriam; Wölfle, Michael; Rominger, Frank
• Is Part Of: Chemistry. Volume 19:Issue 1(2013)
• Page Start: 382
• Page End: 389
• Publication Date: 2012-11-13
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201202004
• Languages: English
• ISSNs: 0947-6539

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>Four different synthetic strategies led to a variety of furan–yne systems that contained an aryl system in the tether. Due to the short routes to these systems (four steps or less), a small library of substrates could easily be prepared. These were treated with AuCl₃ or with the Gagosz's catalyst Ph₃PAuNTf₂ complex. The AuCl₃‐catalyzed reactions delivered highly substituted fluorene derivatives, a class of compounds of great importance as precursors for luminophores with extraordinary abilities. Conversely, a different mechanistic pathway was observed with the cationic gold(I) catalyst. In the latter case, a mechanistically interesting reaction cascade initiated a formal alkyne insertion into the furyl‐sp³‐C bond, which gave indene derivatives as the final products. This new reaction pathway depends on the aromatic moiety in the tether, which stabilizes a crucial cationic intermediate as a benzylic cation.</p> </abstract>