Synthesis of 1‐Phospho‐3‐benzoxepins via a Silver‐catalyzed Reaction of 2‐Alkynylacetophenones with Diazomethylphosphonates

Abstract A synthetic protocol for construction of 3‐benzoxepin skeleton through a silver‐catalyzed annulation/nucleophilic/ring‐expansion reaction of 2‐alkynylacetophenones with diazomethylphosphonates is described. This protocol provided a series of 1‐phosphonate‐3‐benzoxepin analogs in yields of 39%–95%. The resulting benzoxepins featuring halogen and phosphonate could be further transformed into other derivatives. magnified image