Suzuki coupling microwave-assisted fluorous phase

Fig. 41 Representative example of microwave-assisted Suzuki couplings in fluorous phase. Reagents and conditions [Pd(dppf)Cl2], K2CO3, toluene/acetone/H20, MW 130°C, 10 min, closed system, 78%...

Further examples of microwave-assisted Suzuki cross-couplings involving supported substrates/catalysts or fluorous-phase reaction conditions are described in Chapter 7. 

The time consuming chromatographical purification of heterocycles 28 and 29 slowed down the rate of library production. A phase separation using fluorous chemistry was employed by Zhang and Lu to address the workup and purification of fused 3-aminoimidazo[ l,2-a]pyridines (such as 30) [54]. Thus, attachment of a perfluorooctanesulfonyl tag to aldehydes and subsequent Ugi three-component microwave-assisted condensations with 2-aminopyridines and isocyanides furnished the desired heterocycles 30, which were conveniently isolated by fluorous solid-phase extraction. The fluorous tag could be subsequently used as an activating group in the post-condensation modifications, such as Suzuki-Miyaura cross-coupling reactions. 

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