| abstract |
The present invention provides process for the preparation of polymers comprising at least unit of formula (1), which process comprises the step of (v) treating a compound of formula (5), wherein Y 2 is I, Br, CI or O-S(O) 2 CF 3 , with an S-donor agent, in order to obtain the compound of formula (4), wherein Y 2 is as defined for the compound of formula (5), a process for the preparation of a compound of formula (4) as well as compounds of formula (4). |