Thieno[3,2-b]benzofuran - Synthesis and reactions

Thieno[3,2-b]benzofuran was synthesized starting from benzo[b]furan-3(2H)-one or benzo[b]furan-2-carbaldehyde. Electrophilic substitution reactions such as bromination, formylation, acetylation or nitration, take place in position 2. An electron donating group in position 2 directs further electrophilic substitution into positions 3 and 6, whereas compounds with an electron acceptor in position 2 are substituted exclusively in position 6. Metallation with butyllithium took place in position 2. The H-1 and C-13 NMR signals of the title compound were fully assigned.