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One‐Pot Desilylation/Dimerization of Terminal Alkynes by Ruthenium and Acid‐Promoted (RAP) Catalysis
Author(s) -
Pasquini Chiara,
Bassetti Mauro
Publication year - 2010
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.201000347
Subject(s) - chemistry , ruthenium , alkyne , catalysis , enyne , acetic acid , phenylacetylene , dimer , medicinal chemistry , combinatorial chemistry , selectivity , organic chemistry
The dimerization of terminal arylalkynes promoted by the ( p ‐cymene)ruthenium dichloride dimer/acetic acid system {[RuCl 2 ( p ‐cymene)] 2 /AcOH} can be performed starting from the trimethylsilylethynyl derivatives (12 substrates), deprotected in situ , to afford 1,4‐disubstituted 1‐en‐3‐ynes with high regio‐ and ( E )‐stereoselectivity, at room temperature. The extension of this unprecedented two‐reaction sequence to a diyne substrate affords a fluorene‐based conjugated oligomer. The reaction mixture resulting from the desylilation‐dimerization process dimerizes additional aliquots of phenylacetylene. The one‐pot protocol results in shorter reaction times due to the presence of acetate salts which increase the concentration of active catalytic species, in which the acetate ligand acts as base toward the bound alkyne. The ruthenium source is transformed into a new trihapto‐hexa‐1,3‐dien‐5‐yn‐3‐yl complex, formed by metal‐assisted coupling of the enyne product and the terminal alkyne, and still maintaining catalytic activity. Selectivity, endurance, medium and functional group compatibility are the key features of the catalytic system obtained from the p ‐cymene ruthenium dimer under the one‐pot conditions.