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A Simple and Efficient Copper‐Free Catalytic System Based on a Palladacycle for the Arylation of Alkynes
Author(s) -
Consorti Crestina S.,
Flores Fabricio R.,
Rominger Frank,
Dupont Jairton
Publication year - 2006
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.200505310
Subject(s) - chemistry , phosphine , catalysis , adduct , alkynylation , medicinal chemistry , copper , propyne , combinatorial chemistry , palladium , stereochemistry , organic chemistry
The palladacycle [Pd( k 2 ‐C , N ‐C(C 6 H 5 )C(Cl)CH 2 NMe 2 )(μ‐Cl)] 2 ( 1 ) derived from the chloropalladation of 3‐(dimethylamino)‐1‐phenyl‐1‐propyne and its phosphine adduct [Pd( k 2 ‐C , N ‐C(C 6 H 5 )C(Cl)CH 2 NMe 2 )P(4‐CF 3 C 6 H 4 ) 3 (Cl)] ( 3 ) promote the alkynylation of bromo‐ and iodoarenes under relatively mild reaction conditions. The coupling of iodoarenes and activated bromoarenes with terminal alkynes can be conducted at room temperature. Turnover numbers have been achieved up to 10 5 with iodoarenes and up to 94 for deactivated bromoarenes but at higher temperatures (120 °C). Selective poisoning experiments (Hg, Collman and Crabtree tests) suggest that soluble Pd(0) species are the most probable catalytically active species involved in this C sp 2 –C sp coupling reaction.