Oligomer Syntheses on a Solid Support

As a result of these low isolated yields of products, we altered our synthetic pathway through the route of traceless cleavage in order to obtain 

The preparation of resin-bound alkyne 29 followed a parallel synthesis. The subsequent split-and-pool synthesis of individual oligomers was performed in micro-reactors, specifically MacroKans, with unique identification system. Resin-bound monomer 29 sealed in MacroKans were subjected to a Pd/Cu-catalyzed cross-coupling with monomers 30a-e in EtjN. This catalyst (Pd(dba)j/PPh/CuI) solution was pre-mixed with stirring at 70 °C for 2 h prior to use. The suspended MacroKans were heated in a screw cap tube at 65 °C for 44-48 h. At the completion of the coupling reaction, the MacroKans were collected and washed according to a literature procedure. 

In order to monitor resin loading, 30a and 30e were liberated into corresponding dimers via the traceless cleavage method by sonication at 50 °C 

This study presents a fast combinatorial synthesis of oligo(phenylene ethynylene)s incorporating diversity of substituent group, which could be used to deduce structure-activity relationships. 

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