One-pot synthesis of benzothiazolines and napthathiazolines via cascade ortho-lithiation, cyclisation and elimination of N-arylsulfonyl lactams

摘要

Ortho-Lithiation of cyclic aryl sulfonamides in the presence of phosphoryl chloride provides a very simple entry to fused polycyclic sultams (benzothiazolines and naphthathiazolines). Sulfonamides have found many important applications in organic synthesis including as protecting groups, chiral auxiliaries and directed metallation groups (DMGs). In addition, the sulfonamide functionality is present in many biologically active compounds where it can function as a stable amide equivalent. In particular, cyclic sulfonamides (sultams), of which there are many variations, are well documented in the literature.