1. Computational study of the copper-free Sonogashira cross-coupling reaction: shortcuts in the mechanism
- Author
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Jaana Tammiku-Taul, Lauri Sikk, and Peeter Burk
- Subjects
inorganic chemicals ,General Engineering ,Sonogashira coupling ,chemistry.chemical_element ,Medicinal chemistry ,Oxidative addition ,Coupling reaction ,Reductive elimination ,chemistry.chemical_compound ,Acetylene ,chemistry ,Phenylacetylene ,Bromide ,Palladium - Abstract
The sec-butylammonium salt catalysed oxidative addition of phenyl bromide to tris(triphenylphosphane)palladium and reaction of phenylacetylene with cis-Pd(PPh3)2(Ph)Br were modelled using DFT B97D/cc-pVDZ method to study the mechanism of the copper-free Sonogashira cross-coupling reaction. sec-Butylammonium bromide influences the oxidative addition by coordinating with palladium catalyst and the resulting product is trans-Pd(PPh3)2(Ph)Br, not the corresponding cis-compound, which is formed in the absence of salt. The transition-state energy of this oxidative addition mechanism is very close to the previously reported biligated oxidative addition pathway. Reaction of acetylene with cis-Pd(PPh3)2(Ph)Br can lead to either a transor a cis-Pd(PPh3)2(CCPh)Ph complex, while only the latter is capable of undergoing reductive elimination.
- Published
- 2013