The cyclization and functionalization reactions involving N-phenacylpyridinium salts

Pyridinium salts have been used as starting materials and intermediates in 1,3-dipolar cycloaddition with dipolarophiles. Among them, N-phenacylpyridinium salts can easily react with dipolarophiles due to having a good electron-attracting COPh group. This group can stabilize pyridinium ylide generated in situ from N-phenacylpyridinium salts. The synthesis of a wide variety of biologically active N-, O-, and S-heterocycles, as well as carbocycles, can be achieved from N-phenacylpyridinium salt precursors. This review highlights important cyclization and functionalization reactions, involving N-phenacylpyridinium salts.

Graphical abstract

N-phenacylpyridinium salts, an important subclass of pyridinium salts, serve as an intermediate, as well as a starting material in the synthesis of a diverse range of N-, O-, and S-heterocycles, as well as carbocycles. The construction of important biologically active molecules, such as indolizine, pyridine, quinoline, pyrrole, azepine, dihydrofuran, and chromene, can be achieved from N-phenacylpyridinium salt precursors. This review highlights cyclization and functionalization reactions, involving N-phenacylpyridinium salts.