Sonogashira heterogeneous catalyst development

Recently it has been observed that NCBs have been used as a support for heterogeneous catalyst due to its hollow core, mesoporous and ball-like structure. Park et al. [70] developed Pd(OAC)2 catalyst supported on NCBs and applied it for the synthesis of 2-substituted benzofuran from u-iodo phenol and various substituted terminal alkynes using Sonogashira cross-coupling reaction under copper and ligand-free condition. 

Activated charcoal is used as a heterogeneous support to prepare different supported metal catalysts because of its robustness and inertness. Recently Felpin et al. [72] developed a bimetallic Pd-Cu heterogeneous catalyst supported on active charcoal and used it to synthesize benzofurans by the same protocol of Sonogashira alkynylation-cyclization sequence (Scheme 53). 

F.X. (2010) Recyclable heterogeneous palladium catalysts in pure water sustainable developments in Suzuki, Heck, Sonogashira and Tsuji-Trost reactions. Adv. Synth. Catal., 352 (1), 33-79. 

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