Syntheses of 7-substituted anthra[2,3-b]thiophene derivatives and naphtho[2,3-b:6,7-b']dithiophene.

7-R-Anthra[2,3-b]thiophene derivatives (1, R = H, Me, i-Pr, or MeO) are prepared in three steps (in average overall yield >50%) starting from (E)-4-RC6H4CH2(HOCH2)C=CI(CH2OH). The latter are commercial or readily prepared from 2-butyne-1,4-diol and ArCH2Cl (both costing <1 cent/mmol) at 10 g scales. These allow for the selective formation of (otherwise unattainable) higher solubility 7-derivatives. Similar methods allow for the preparation of naphtho-[2,3-b:6,7-b']dithiophene 2 using equally low-cost starting materials.