... i–iii iv vi A novel acylative ring cleavage of benzothieno[3,2-b]pyran-4-ols: application to the synthesis of dibenzothiophenes and fused-ring derivatives Christopher D. Gabbutt,* John D. Hepworth, B. Mark Heron and Jean-Luc Thomas Department of Chemistry, University of Hull, Hull, UK HU6 7RX. E-mail: cdgabbutt@chem.hull.ac.uk ... 13). Compound 8: d (CDCl3) 7.78 (1H, d, J 12.2, NCHCHCMe2). ...