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Oxidative addition of activated aryl-carboxylates to Pd(0): divergent reactivity dependant on temperature and structure
Ist Teil von
Dalton transactions : an international journal of inorganic chemistry, 2020-11, Vol.49 (45), p.1667-1671
Ort / Verlag
England: Royal Society of Chemistry
Erscheinungsjahr
2020
Link zum Volltext
Quelle
Alma/SFX Local Collection
Beschreibungen/Notizen
With the exception of activated sulfonate esters, oxidative addition of Ar-O bonds to Pd(0) complexes is extremely rare. This has led to a general perception that Pd-catalyzed cross-coupling is not feasible with O-based electrophiles such as aryl esters. We report that pyrone and coumarin esters do undergo oxidative addition to Pd(PCy
3
)
2
, with Pd insertion into either the acyl-O or Ar-O bond. Addition of the acyl-O bond to Pd(0) is kinetically favoured and reversible, while addition of the Ar-O bond is thermodynamically favoured. Using a larger and more electron-rich pivalate derivative disfavours acyl-O cleavage, enabling selective oxidative addition of the Ar-O bond and corresponding catalytic cross-coupling.
Strong C-O bonds in pyrone and coumarin esters can undergo oxidative addition to Pd(0), with the reaction conditions and substrate structure controlling the outcome.