Annulation of Eight- to Ten-Membered Oxaza Rings to the Benzo[b]thiophene System by Intramolecular Nucleophilic Displacement

Abstract

Concise synthetic routes to 2H-benzo[b]thieno[3,2-b][1,5]oxazocin-6(3H)-one, and the new benzo[b]thieno[3,2-b][1,5]oxazonin-7(2H)-one and 2H-benzo[b]thieno[3,2-b][1,5]oxazecin-8(3H)-one systems, have been developed based on intramolecular nucleophilic displacement in the key ring forming step.