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Recyclable Hybrid Silica‐Based Catalysts Derived from Pd–NHC Complexes for Suzuki, Heck and Sonogashira Reactions
Author(s) -
Borja Guadalupe,
MongeMarcet Amàlia,
Pleixats Roser,
Parella Teodor,
Cattoën Xavier,
Wong Chi Man Michel
Publication year - 2012
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201200205
Subject(s) - sonogashira coupling , chemistry , tetraethyl orthosilicate , heck reaction , phenylacetylene , suzuki reaction , aryl , catalysis , organic chemistry , combinatorial chemistry , turnover number , palladium , polymer chemistry , alkyl
Two silylated Pd–NHC complexes were immobilized on hybrid silicas by sol‐gel cocondensation with tetraethyl orthosilicate (TEOS) and performed well as recyclable catalysts towards the Heck, Suzuki, and Sonogashira coupling reactions. Remarkable conversion and recyclability were achieved in the Suzuki reaction with a challenging aryl chloride. No side products and no undesired homocoupling were observed in Suzuki or Heck reactions, which facilitates the final purification step for the cross‐coupling products. High turnover numbers and turnover frequencies were found for copper‐ and phosphane‐free Sonogashira reaction between p ‐bromoacetophenone and phenylacetylene.