反应详情

As outlined in Scheme 3, the preparation of 2,9-dibromo-5,6-dioctylnaphtho[2,1-b:3,4-b′]dithiophene started from 1,2-dichlorobenzene. A nickel-catalyzed Kumada coupling reaction between 1,2-dichlorobenzene and freshly prepared octylmagnesium bromide offered 1,2-dioctylbenzene. Iodination of 1,2-dioctylbenzene followed by palladium-catalyzed Suzuki coupling reaction with 3-thiophene boronic acid provided 4,5-bis(3-thienyl)-1,2-dioctylbenzene at high yield.18 5,6-dioctylnaphtho[2,1-b:3,4-b′]dithiophene was then prepared via oxidative photocyclization by irradiation of a diluted toluene solution of 4,5-bis(3-thienyl)-1,2-dioctylbenzene under ambient conditions in the presence of a catalytic amount of iodine.24,25 Subsequent bromination using NBS in a mixed solvent of chloroform/acetic acid offered the co-monomer 2,9-dibromo-5,6-dioctylnaphtho[2,1-b:3,4-b′]dithiophene