G. Barbarella, M. Zambianchi
1994
Citations
0
Influential Citations
19
Citations
Journal
Tetrahedron
Abstract
Abstract The synthesis of 3,4′- and 3,3′-di(2-hydroxyethyl)-2,2′-bithiophene, building blocks for the preparation of regioregular head-to-tail and head-to-head polyhydroxyl oligothiophenes, is described. The synthesis was achieved through Pd(PPh 3 ) 4 catalyzed cross-coupling of 2- and 5-trimethylstannanes of 3-[2-(tetrahydropyranyloxy)ethyl] with the corresponding 2 bromo derivative, followed by deprotection of the hydroxyl groups in acidic medium. The synthesis of 3,4′-[2-(tetrahydropyranyloxy)ethyl]-2,2′-bithiophene afforded a non-negligible amount of the 4,4′-regioisomer, arising from the homocoupling reaction of the 5-trimethylstannane. Conversion of 3,3′-di(2-hydroxyethyl)-2,2′-bithiophene to the corresponding sodium sulfonate salt was shown to occur with 55% yield, indicating that polyhydroxyl oligothiophenes are, in fact, useful precursors in the preparation of water soluble ′self-doping′ oligothiophenes.