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Air‐Stable, Phosphine‐Free Anionic Palladacyclopentadienyl Catalysts: Remarkable Halide and Pseudohalide Effects in Stille Coupling
Author(s) -
Crawforth Catherine M.,
Fairlamb Ian J. S.,
Kapdi Anant R.,
Serrano José Luis,
Taylor Richard J. K.,
Sanchez Gregorio
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.200505325
Subject(s) - chemistry , halide , phosphine , iodide , catalysis , stille reaction , bromide , allylic rearrangement , succinimide , phthalimide , medicinal chemistry , chloride , polymer chemistry , organic chemistry
The Stille cross‐coupling of allylic and benzyl bromides is shown to proceed efficiently using phosphine‐free dinuclear anionic palladacyclopentadienyl catalysts possessing bridging ( N , O )‐imidate ligands. The type of bridging anion influences the catalytic activity considerably. Halide anions such as chloride, bromide or iodide also influence the catalytic activity but to a far lesser extent than the pseudohalide imidate anions (from succinimide or phthalimide). A Baldwin‐type cooperative effect is seen with 7a using CuI as a co‐catalyst, in the presence of two equivalents of CsF in DMF at 40 °C. In toluene, these additives slow down substrate turnover.