A schematic representation of various judicious approaches for the synthesis of BPA and BSH modified compounds for effective BNCT.

In recent years the chemistry of cyclic iodonium salts has experienced ever‐growing development. The advantages of using cyclic iodonium salts over acyclic iodonium salts are that the reactions between cyclic iodonium salts and various nucleophiles lead, under suitable reaction conditions, to dual arylations in a one‐pot manner and to the formation of new heterocycles. Variously functionalized thiophenes, carbazoles, fluorenes, phenanthrenes and triazolophenanthridines have been synthesized by utilizing cyclic diaryliodonium salts. Various new ladder‐type π‐conjugated systems have also been synthesized by employing cyclic iodonium salts. In this microreview, the recent advancements in the synthesis and application of cyclic diaryliodonium salts are discussed in a systematic and concise manner.

[reaction: see text] A highly practical, general method for catalytic formation of substituted pyridines from a variety of unactivated nitriles and alpha,omega-diynes is given. The reactions which were catalyzed by 5 mol % of dppe/CoCl2-6H2O in the presence of Zn powder (10 mol %) could proceed at rt to approximately 50 degrees C with high functional compatibility and regioselectivity.

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The addition of silver triflate (AgOTf) or silver hexafluoroantimonate (AgSbF 6 ) significantly increased the activity of the 2-(arylimino)methylpyridine/cobalt(II) chloride hexahydrate (CoCl 2 ·6 H 2 O)/zinc catalyst in alkyne cyclotrimerizations thereby accelerating the reaction and enabling the use of unactivated, simple internal alkynes as the monoyne substrate: The rate of reaction was found to be highly dependent on the nature of the counter anion (X À ) and the ligand (L) in the postulated cationic cobalt(I) complex [LCo(I)] + X À .