Triflates solid support catalysts. Suzuki reactions

An alternative to solid-supported catalysts are catalysts that are insoluble themselves [136]. A pyridine-aldoxime ligand was presented and evaluated in the Suzuki-Miyaura reaction using water as a solvent. Using an Irori kan to contain the polymeric catalyst, the reaction could be repeated 14 times without any noticeable reduction in efficiency. The optimized reaction conditions were then used to create a small library of approximately 30 biaryl compounds using aryl iodides, bromides, triflates as well as an activated chloride (Scheme 56) [136]. 

The use of solid supported, recyclable catalysts, is a well-assessed technique in classic organic chemistry, and many exhaustive reviews dealing with this subject are available [105, 115]. The use of solid supported catalysts for library synthesis in solution has also been reported. Among others, Kobayashi et al. presented the use of a new supported scandium catalyst for 3CC reactions leading to solution libraries of amino ketones, esters, and nitriles (24-member model discrete library) [116], or to quinolines (15-member model discrete library) [117], and Jang [118] presented a polymer bound Pd-catalyzed Suzuki coupling of organoboron compounds with halides and triflates. This area was also briefly reviewed recently [119]. 

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