Diaryl iodonium salts preparative methods

Diaryliodonium salts. lodosoarenes are useful for the preparation of diaryl-iodonium salts. One method involves Friedel-Crafts type condensation with an aromatic compound in the presence of acids. For example, a cold solution of 5 g. 

Because of the multitude and diversity of iodonium salts and zwitterions, some of which are labile or are prepared for specific purposes, their preparative methods are discussed in Chapter 8, for diaryl iodonium salts and related compounds, Chapter 9 for perfluoroalkyl, alkenyl and alkynyl phenyliodonium salts and Chapter 10 for zwitterionic iodonium compounds. In addition, the preparation of some lesser known reagents, including 2-iodosylbenzoic acid, is given in Chapter 12. 

A large number of methods are available for the preparation of diaryl iodonium salts (hereafter simply iodonium salts). Among them, there are some of general applicability or improved efficiency. Examples from each major category are given. 

A very mild and general method for the preparation of diaryl- and heteroaryliodonium triflates is based on iodonium transfer reactions of iodine(III) cyanides with the respective aryl- or heteroarylstannanes [146,148, 399-401]. Specifically, (dicyano)iodonium triflate (277), generated in situ from iodosyl triflate and MesSiCN, reacts with tributyltin derivatives of aromatic and heteroaromatic compounds to afford the corresponding symmetrical iodonium salts under very mild conditions (Scheme 2.80) [389,390]. 

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