Synthesis of Benzo[1,2-b:4,5-b']dithiophene and Benzocondensed Thiaheterocycles

A two-step synthesis of benzo[1,2-b:4,5-b']dithiophene (BDT) was carried out starting from 3-thiophene carbaldehyde as the sole thiophene precursor. This method involves the selective lithiation of the 2-position of 3-thiophenecarbaldehyde ethylene acetal, followed by the condensation with 3-thiophenecarbaldehyde and subsequent dehydrative cycloaromatization of the dithienylmethanol intermediate to give BDT. This synthetic pathway was extended to other thiophene benzocondensed heterocycles.