Oligothiophenes used as cores in dendrimers

Reagents and condition (i) Tributyl(thiophene-2-yl)stannane, PdCl2(PPh3)2, DMF, 90 °C (ii) NBS, AcOH, CHCI3, 0 °C then rt. (iii) Stannylated dendron, Pd(PPh3)4, DMF, 90 °C. 

Frechet et al. subsequently prepared dendronized oligothiophenes 5.68 and 5.69 up to a nonamer. The aliphatic ether dendrons were attached either to the a-position of a terminal or to the P-position of a central thiophene unit (Chart 1.77) [511]. The syntheses were performed by iterative NBS brominations and Pd°-catalyzed Stille-type coupling reactions. These materials revealed that the attachment of dendrons 

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