Construction of Sulfonyl Dibenzofused Medium‐Size Oxacycles via Bi(OTf)₃‐Catalyzed Friedel‐Crafts‐Type Annulation

Abstract

Herein, Bi(OTf)3‐catalyzed Friedel‐Crafts‐type annulation of sulfonyl o‐hydroxyacetophenones with benzofused cycloethers is described. This single‐step strategy provides a variety of functionalized dibenzofused medium‐size (9–12) oxacycles through the formation of carbon‐carbon and carbon‐oxygen single bonds. Further, the oxidative application of target oxacycles was investigated. The chemical structures of the key products were determined based on the single‐crystal X‐ray analysis. In the overall process, water was generated as the byproduct.

One-pot synthesis of benzofused 8-oxabicyclo[3.3.1]nonanes via GaCl3-mediated cyclocondensation of o-allylbenzaldehydes and 1,3-dicarbonyl synthons

“…The results indicated that the refluxing temperature (101 °C) was suitable to enhance the yield. According to our previous reports on the bismuth-catalyzed annulations, 15 BiCl 3 was screened next. No obvious improvement in the isolated yield of 6a was detected (entry 4, 75%).…”